Samsung A51 disconnects from cellular network - Samsung Galaxy A51 Questions & Answers

Hi
I'm having a strange problem with my new A51, with two SIM cards in it.
After an indeterminate time the phone disconnects from cellular network.
It still shows on to the both cards the signal strength, but the phone no longer receives calls or has internet access throw cellular network.
And if I call any of the SIM card numbers from another phone, I get a network message saying the phone is disconnected.
All other functions on the phone seams to be ok. Turning wifi on and off has no effect in reconnecting to the cellular network.
But... If I try to call from A51 to any other number, the phone reregisters on cell network, the call is done and from that point on, all goes to normal. I can receive calls again and access the internet using the cellular network...
I went to the store were I bought it, and the gave me another one, but with the exact same problem.
So I believe is not a hardware problem.
I believe now that It could be a SIM problem, on one or both SIMS, which is odd
A software problem on A51 the need's to be patched, which is odd because it has effect on the most basic feature of the phone, which is receiving calls...
A strange behavior of the phone with my cellular service provider, which is odd too...
I'm trying now with only one SIM to see if the problems happens too...
Can any one suggest any other test or debug to try to clarify this issue ?
Thanks

antoniomch said:
Hi
I'm having a strange problem with my new A51, with two SIM cards in it.
After an indeterminate time the phone disconnects from cellular network.
It still shows on to the both cards the signal strength, but the phone no longer receives calls or has internet access throw cellular network.
And if I call any of the SIM card numbers from another phone, I get a network message saying the phone is disconnected.
All other functions on the phone seams to be ok. Turning wifi on and off has no effect in reconnecting to the cellular network.
But... If I try to call from A51 to any other number, the phone reregisters on cell network, the call is done and from that point on, all goes to normal. I can receive calls again and access the internet using the cellular network...
I went to the store were I bought it, and the gave me another one, but with the exact same problem.
So I believe is not a hardware problem.
I believe now that It could be a SIM problem, on one or both SIMS, which is odd
A software problem on A51 the need's to be patched, which is odd because it has effect on the most basic feature of the phone, which is receiving calls...
A strange behavior of the phone with my cellular service provider, which is odd too...
I'm trying now with only one SIM to see if the problems happens too...
Can any one suggest any other test or debug to try to clarify this issue ?
Thanks
Click to expand...
Click to collapse
My wife have exact same issue with single sim.

Related

[Q] anyone getting sim card does not allow connection to this network?

I have gotten this message 3 times in the last 5 days. Each time I need to do a reboot to restore cellular/sms service (toggling airplane, wifi, bluetooth, sync, and 4g do not restore cellular/sms). The phone has the same AT&T sim card since day 1 and I have never removed it.
Is this a faulty phone, sim card or both?
gtabfish said:
I have gotten this message 3 times in the last 5 days. Each time I need to do a reboot to restore cellular/sms service (toggling airplane, wifi, bluetooth, sync, and 4g do not restore cellular/sms). The phone has the same AT&T sim card since day 1 and I have never removed it.
Is this a faulty phone, sim card or both?
Click to expand...
Click to collapse
Did the sim come with the phone? ATRIX 2 needs newest of sim cards to function properly. If that's not the problem then I'm not to sure.
Sent from my MB865 using XDA App
Yes, same sim card that came with phone.
Could be a faulty Sim, i've had that happen before with other phones, just go to at &t and show them the problem, they should replace it for you!
Sent from my MZ617 using Tapatalk
(Hope you understand my english)
I wasn't able to solve this problem about an year. But did. And totally sure that it is Device's defect (in some cases it is a ROM deffect as in my case, in other - hardware. Smth like stack overflow issues at GSM controller or so). A year ago when I had face this "sim card does not allow connection... " problem, there are no google serch results on this keywords request. Any. To remove this message I was ought to reboot my device every time it appears. And I was thinking that it is normal behaviour for my device. But now there are lot of complainings at the web ( minimum 5 of Galaxy Tabs P1000, thousands of HTC Disire, few motorolla Deffy, 10 Galaxy Ace, few of Nexus S and so on), so I understand that I'm not alone, and problem is known. So I went to Samsungs Service and they confirmed that it is famous problem, have flashed my phone with some magic ROM (magic because it is official but does not available anywhere in the web, XDA or samsung sites! ) and now my phone works fine. Any other solutions like battery removing, *#*#4636#*#* sirvice menu, new sim-card, flashing variety of modems and roms, didn't helps me. This is not faulty sim. This is serious device's defect. Bring your phone to manufacturer and let them repair it or give your money back. This is their problem not your.
using old 3g prior sim card
With ATT---If you took your old 3g sim card out of old phone and used it. You will get this message. You need to activate the 4g card that came with phone
537magspc said:
With ATT---If you took your old 3g sim card out of old phone and used it. You will get this message. You need to activate the 4g card that came with phone
Click to expand...
Click to collapse
Not true.I'm using my old 3g sim with zero issues.
Sent from my MB865 using XDA
Same issue in Mumbai India
CS4 said:
(Hope you understand my english)
I wasn't able to solve this problem about an year. But did. And totally sure that it is Device's defect (in some cases it is a ROM deffect as in my case, in other - hardware. Smth like stack overflow issues at GSM controller or so). A year ago when I had face this "sim card does not allow connection... " problem, there are no google serch results on this keywords request. Any. To remove this message I was ought to reboot my device every time it appears. And I was thinking that it is normal behaviour for my device. But now there are lot of complainings at the web ( minimum 5 of Galaxy Tabs P1000, thousands of HTC Disire, few motorolla Deffy, 10 Galaxy Ace, few of Nexus S and so on), so I understand that I'm not alone, and problem is known. So I went to Samsungs Service and they confirmed that it is famous problem, have flashed my phone with some magic ROM (magic because it is official but does not available anywhere in the web, XDA or samsung sites! ) and now my phone works fine. Any other solutions like battery removing, *#*#4636#*#* sirvice menu, new sim-card, flashing variety of modems and roms, didn't helps me. This is not faulty sim. This is serious device's defect. Bring your phone to manufacturer and let them repair it or give your money back. This is their problem not your.
Click to expand...
Click to collapse
I have exactly the same issue randomly at times when I try to register on network manually (MTNL Dolphin 3G - Mumbai). Unrooted MB865 ver 2.3.6 & updated on 18th May 2012 to System Ver 55.28.37.MB865.AsiaRetail.en03. If I keep the setting as Automatic in Type of Network & Operator it functions fine fluctuating between Dolphin for local access & CellOne on roaming access in the same area based on cell tower connection the phone registers on alternating between "E" & "H" automatically based on cell mast direction proximity, however if I select 3G only and uncheck automatic for operator then the phone searches for signal for a very long time and fails to show any operator saying "no connection available" & sometimes when "Dolphin" network does appear and try to select manually get the error as "this sim card does not allow connection to this network". I did complain with the service provider and they were supposed to get back to me after checking in their switchboard exchange where I also provided them my SIM number in addition to my cellphone number(no response). Also as is case with poor service of all Indian cell network providers even in urban cities, also face random peculiar issue of call not being received inspite of signal available on the phone & network asking me to recheck the number I have dialled while placing outgoing calls though it is ok and signal is sufficient. Also "Network Speed Booster" app looks like a lot of bull (any other good apps??)
I needed to know using the secret Menu *#*#4636#*#* for 3G GSM service which kind of network I should ideally select for best results & does this setting override the regular menu network settings??
I get "G", "E", "H" randomly based on my locations but no "3G" or "H+" and further at times these icons are grey and sometimes blue and in either cases randomly at different locations sometimes data throughput is not there as only one of the arrow shows active blinking. Any advise on the status based on colors and the blinking of the arrows?? Thanks!

[Q] Sim not connected to network

Hi,
I have H60-L02 version with B307 from some time now and lately I noticed that, without warning, one or both sims are been disconnected from network, putting me in the situation in which I cannot make or receive calls. If I change from 2G to 3G on sim 1 it reconnects.
The fact which is more annoying is that in disconnected state on the status bar it shows that I have network signal on both sims. For checking if I'm effectively connected to network I have to go in "Settings-About phone-Status-Network" and verify the Service state.
Anyone had this problem, and if so, is there a workaround ?
Thank you.
I got similar problems with the SIM card. I've got the international h60-l04 on stock firmware with one SIM slot and the mobile connection fails every time. The Status Bar says there is a connection, but it isnt stable. It switches every few seconds.
I tried to delete the APN, forcing 2G and 3G and havent got a sollten, yet. I first thought it's a firmware failure.
Is there any solution for this? I have the similar problem as well... My model is H60-L02.
Thanks..

[Not-Fixed] How to install new Z3 D6603 LTE on AT&T network

[Not Fixed] see bottom of this post.
It is fairly easy to install a new D6603 to work completly on the AT&T network. It is not so easy to find the answer of how to do it in the threads and posts. I tried many suggestions and wasted a lot of time. Hopefully this will save you from that fate.
First you must know that you can't use the IMEI number of your new phone if you want it to work completly as it should. If you use the Z3 IMEI you will have trouble with data of various sorts and the phone will go off line when on LTE after 20 or 30 minutes and you will not receive calls or SMS messages. I do not know why but it has been suggested that the AT&T network does not recognise this phone so it causes trouble.
If you have an AT&T nano-sim from your old phone then just put it in the phone. (Cut downs work but can cause other problems some say.) When the SIM is inserted for the first time into a new phone there is a prompt that asks if you want to download the APN. Hit 'yes' and the phone downloads the APN itself.
If it does not ask then go to Settings>More>Mobile Networks>Prefered Network Type and be sure LTE (Preferred) is selected. Then connect your phone to the internet and then go to Settings>More>Internet Settings and select AT&T. You should be good to go.
If you need to get a nano-sim then go to the AT&T store or call and they will give you one or send you one for free. You will need to use the IMEI number from a LTE phone that is already on the AT&T system. You can use your old phone or borrow the number from someone. If the rep installs the sim in the Z3 with the 6603 IMEI don't worry. Just call support later and tell them you sent your new phone back and want to go back to your old IMEI or have a new IMEI (from an existing AT&T phone). They will enter it and off you go. The phone from the IMEI will show in the picture on your account page. Big deal!
Update: This worked for hours last night but this morning it is back to not receiving calls. Simply turning wifi off and it began to receive calls as GPRS was switched back on. My wifi was on which has been said to cause problems. I will test with wifi off and report back. Had "no service" instead of AT&T on upper left of lock screen. A full shut down for several minutes than re-boot solved that.
YMMV. I've been on ATT with a Z3 purchased from Sony store for several months and it was registered in an ATT store by scanning the IMEI off the box followed by updating Internet settings in Setup. ATT online shows unknown model but everything works including LTE and MMS. There is something else involved when problems like this occur probably some setting not getting reset. I registered the Z3 on a new line with a new Sim card because I wanted to take my time moving stuff off my old phone--this may have avoided the problems.
JudH said:
YMMV. I've been on ATT with a Z3 purchased from Sony store for several months and it was registered in an ATT store by scanning the IMEI off the box followed by updating Internet settings in Setup. ATT online shows unknown model but everything works including LTE and MMS. There is something else involved when problems like this occur probably some setting not getting reset. I registered the Z3 on a new line with a new Sim card because I wanted to take my time moving stuff off my old phone--this may have avoided the problems.
Click to expand...
Click to collapse
I've also had no problems with my Z3 on AT&T. Works great, receives sms/mms immediately, etc..
esheesle said:
I've also had no problems with my Z3 on AT&T. Works great, receives sms/mms immediately, etc..
Click to expand...
Click to collapse
AT&T's system sometimes takes a while to get updated with new IMEIs that trigger LTE provisioning for a users' account.
Once your account is provisioned for LTE you never have to worry about it again, but sometimes if you have a phone the system doesn't recognize, it is a pain to get AT&T to properly provision your account. Supposedly properly trained in-store reps can do it - the key being "properly trained" - Never try to do anything "unusual" by calling AT&T customer service, and NEVER use a franchise/kiosk in-person for service - make sure you're at a corporate-owned store! Even then, some stores might have incompetent staff. I've been lucky that all of my local corporate stores are pretty well staffed.
So you are saying that your Z3's with wifi and LTE on with AT&T are working as they should?
With LTE off my phone responds normally with wifi on. With LTE and wifi on it will not respond to calls after a 30 minute sleep. It does not show missed calls. Calls go straight to voice mail after 2 rings. Could you tell me what level your LTE dBm's are? Thanks!
I was told not to give them my imie# but, after recvng the minisim I had to call them in order to 'provision' it to work at all and they needed that #. I have never had any problems personally and am assuming this may be because you gave them the wrong #. Again I am only guessing. Oth, if I had had a different imie to give, I would have done so myself.
It is very strange and I am feeling it is more signal strength related than how you provision your phone. (Once it is provisioned correctly.) It seems that more people have less problems when they already have a nano-sim and just plunk it in the new phone. This might indicate that they already had a strong signal from the get go. My old HTC One + get's a better signal than the Sony in the same locations with the same (new) SIM. With the Devilcase bumper on it gets 5% less. My very limited tests yesterday seemed to indicate that it was signal strength related. I am not enough of a conspiracy theorist to imagine that AT&T would program their system to not function correctly with sims that are provisioned with these Sony phones which they are obviously ignoring for some reason. Or am I?
I had all kinds of problems with the Z3 on AT&T. The IMEI caused an issue since AT&T linked it to a flip phone and therefore couldn't provision LTE. I changed it to an old AT&T LTE device and then I was able to get LTE but was having the same issue with calls going directly to voicemail and texts showing up hours later in bunches. I found the solution was to switch off LTE in the quick settings menu. All calls and texts came through and on time while LTE was off. If I needed a data boost to stream, I turned it back on until I was finished streaming. This was while on KitKat. After upgrading to Lollipop, I was able to keep LTE turned on and calls and texts still arrived on time.
I use data rarely. Mostly wifi. If I don't leave LTE on, my phone reverts to wcdma preferred. And why can't LTE just work without me having to constantly turn it back on? What bugs me is having the APN settings greyed out. I want to be able to turn it off. If anything it seems the phone itself is preventing me from accessing the sim. It feels like I'm borrowing something which contains lots of MY private data. I know my phonebook is stored locally but I also noticed there is no option of specifying the sim or not. Anybody know how to switch APN on and off? In fact, overall even rooted, I still feel like I have almost no power over it. I can't even disable the cellular connection without going full on airplane mode and I do not trust that. I don't even fly so that needs work for sure. Dumb question but could I buy a working nanosim from say 7-eleven that my apn switch will work with?
"Anybody know how to switch APN on and off?"
On my Z3 on OTA stock Lollypop I have an icon in quick settings to turn LTE on and off. Drag two fingers down from the top of the screen. If no LTE icon then select the pencil icon at the top and select the LTE icon. There is also a mobile data icon switch there.
To turn off your radio completly you can get the Advanced Signal Status app and select additional info at the bottom and click phone information and turn off radio. Probably a number of ways to do it but that is one.
Sim contact storage was a way to move information from phone to phone. You can still do it but not really necessary with cloud backup and storage. Google does it for me without me having to do anything which I like. I still save contacts to the sim just because I can. Export and import in your contacts app menu.
johnboatcat said:
So you are saying that your Z3's with wifi and LTE on with AT&T are working as they should?
With LTE off my phone responds normally with wifi on. With LTE and wifi on it will not respond to calls after a 30 minute sleep. It does not show missed calls. Calls go straight to voice mail after 2 rings. Could you tell me what level your LTE dBm's are? Thanks!
Click to expand...
Click to collapse
Works fine here. I don't pay attention to the dBm estimates since these aren't measured with calibrated test equipment and vary widely. Those numbers are basically worthless.
The only valid comparison is data performance in a given environment (ideally a difficult weak-signal one) - and at my desk with very weak signal, every phone I've ever used performs similarly to the Z3.
"Those numbers are basically worthless."
True, but we have narrowed this down to the possibility that it might be signal related so it is worth a shot. If people whose phones are working fine would measure the LTE dBm on Advanced Signal Status at the location where their phone sits and works well the most we might possibly see some measure of difference in the phones that are not working. Most of the non-working phones seem to work sometimes so signal strength is the next best parameter to rule out. Thanks!
Here are the screen shots of my phone with LTE on, LTE and wi-fi and LTE off and wi-fi.
How do the working phones compare? Does your CDMA (voice) also go to 0% when LTE is on and GSM = n/a?
Thanks. I think adv sig nfo actually works. I'm amazed actually. I can't find the phone's native greyed out apn switch anyways which really makes no sense.

Help with s8+ roaming connectivity

I am currently in Italy using a Vodafone UK sim card, it's been working perfectly (apart from randomly dropping complete signal periodically) but now it's just completely died, as in it won't find a signal at all to connect to any network let alone data roaming. I have contacted Vodafone who said there's nothing wrong at their end and the worst thing is it was working perfectly till this evening. So now it sometimes says emergency calls only or just the ring with a line through it as it cannot find any signal at all. I have tried doing manual network operator selection and automatic but still nothing... Any ideas? It's a g9550 128/6gb
Update I now have 3g data but it says "no network connection" and I cannot send receive texts or phone calls, yet I have full data...
@nugget123
Consequences of buying a CN/HK variant....
They usually have network connectivity issues, not surprising. Try removing the SIM card, turning the phone off, wiping cache in recovery, insert the SIM card, and then reboot. Then manually go and search for a network in settings and force it to connect to Vodafone Italy, should work.
It's working now again, I didn't do anything lol it just started working on its own accord! I'm now in Switzerland and all is good. My life is empty without my phone
It always happens to me when abroad. I am on O2. I have to select network manually and pickup different to the one which auto connect shows emergency calls only. Looks like some cells allowing me to connect but won't pass through calls
Do you also have a usa/china variant?
No, o2 UK from Samsung

No Service after turning on Mobile Data

I have a network issue with my OnePlus 8T. Whenever I enter an area that doesn't have great signal, if my phone connects to 4G, I completely lose all signal and the phone will read "No Service" or "Emergency Calls Only". The best thing I can do is toggle Airplane mode or restart the phone to fix it. The issue does not occur if I set my phone to 2G/3G only. My phone will have signal absolutely everywhere, there isn't a spot that I know of that doesn't get reception. However, the moment I tap "Mobile Data", if the phone connects to 4G and the signal isn't 50% or better. My phone just loses all network on the spot and refuses to return unless I do the two things I listed above. I've been in contact with my service provider, tried swapping SIM slots and cards, reset my network, verified APN is properly setup. Just about everything by now. Does anybody know of a possible solution to this?

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