Cellular Data Dropping While in Transit

Thanks for responding. I did look & I don’t have that turned on BUT my phone says that I need a new battery (IPhone 8 plus).

So, I’ll get a new battery & see if there’s any improvement. Also will try the airplane mode on/off trick if need be. 

one thing I'd recommend trying,  as I suspect that this might be power/battery feature, is to disable battery saving mode.  I can be 100’ away from TMobile 5g tower with 5bars and apps showing  ‘Not connected to the internet ‘.  airplane mode cycles fixes it until next.time.  This, I suspect is handset or NAT gateway issue (dhcp?)

Having the same problem - dropping all data when out & about town. Phone shows no bars & says SOS. I’ve had TMobile for years & have been really happy with the service until the past month or so. I hope that TMobile is reading through these complaints as I’m afraid I might have to go back to the dreadful Verizon with the terrible customer service but reliable coverage.

I did actually get mine working. I had to erase everything and set up as a new phone and instead of restoring from a backup (from my previous iPhone) I set it up as a complete new phone and downloaded all my apps again. It must have been because I went from iPhone XR to 12 and it didn’t like bits of my restore from the XR. 

I have a Samsung s21 . My phone has been doing the same thing. Losing network 20 some times a day. Went through a bunch of steps with tmobile tech. Nothing fixed it. Was also tokd to do a cache wipe but afraid I'll lose stuff on my phone if i don't back up memory.  Hearing all these comments and complaints tells me that probably won't work anyway. 

That’s what I was thinking and had a support call with a Senior Apple consultant from California. It’s just frustrating that my old iphone (that my girlfriend now has) works fine. I’ve got an appointment this weekend here in the UK at my Apple Store although even if they swap the phone I’m still not sure if I can test it as won’t be in the USA for a while. The Apple consultant said that she has heard of the problem before. It’s also weird that it’s the exact same problem that the posters above mention (and I assume they live in the USA). My phone works fine here in England.

if you tried her sim card in your phone and it still did it..then tried your sim card in her phone and it worked fine...everything is pointing right at your phone being the culprit. if the problem followed the sim card then it would be sim card related..since it didnt follow and stayed with your phone no matter the sim card then it points right back at the problem being your phone. since its a European device it might be missing certain bands that are used here in the U.S that her phone actually has on it.

I’ve had this exact problem. I’m from the UK and my mobile network provider is called Three Mobile. When in the USA my phone locks onto their roaming partner which is T-Mobile. Last week I went to Seattle, Chicago, Washington DC and Philadelphia and after random amounts of time my phone would drop the data signal (4G(LTE), 3G or E) but the little bars would still show sometimes and sometimes not.  I was receiving a Cellular signal (it just seemed to be the data dropping although I never made any calls to test this). This happened about 20 times per day every day in each city mentioned and was 100% annoying. From leaving my hotel to getting to a restaurant 200m up the road it would have lost all data signals! I have a new(ish) iPhone 12 Pro Max. The annoying thing is my girlfriends iphone XR (older phone) picked up the data fine and it never dropped once. I tried her sim in my phone and it did the same thing so not my home network (she’s on exactly the same network and tariff as me). I tried my sim in her iphone XR and it worked perfectly so don’t think it’s a sim issue. I tried switching off 5G in the roaming settings and it didn’t make a difference. I reset my network settings in my iphone 12 and it still didn’t work. I have now completely erased my phone using a computer so that it has to re-download the whole iOs operating system (rather than resetting it from my phone). It’s annoying for me as need my phone for travelling so can’t test it until I’m next in the USA which could be months away and my phone will then be out of warranty (if it’s the phone that’s faulty). Apple suggested I buy a sim to use just in the USA on a different network but I don’t want to have to pay extra as with Three I can use all of my included minutes, texts and data when in USA and all of my previous phones have worked fine there when data roaming. I switched off automatic network selection and tried selecting AT&T and Sprint but my phone won’t allow this as I’m roaming and Three is partnered to T-Mobile. I have noticed in my home country that the 4G (LTE) signal seems to be worse since they starting rolling out 5G. After reading about T-Mobile and Sprint merging I wonder if it has anything to do with that? I was convinced it was my phone but now not so sure. I was reading about channels and someone wrote that the 5G opens channels that some networks can’t use and tries to force your phone onto so drops the data signal but not sure. It’s just frustrating that a phone less than one year old can’t do what a phone from a few years back can! The airplane mode ‘fix’ works but it’s very annoying in this day and age having to effectively reset your network signal just to be able to receive data!

@Mo_Rsa , we are twins because I have a cellspot at my house as well. I’m wondering if that is part of this. 

I’m thinking the phone gets connected to the T-Mo network on the Cellspot, but then the phone has trouble getting re-connected to a “real” T-Mo tower.  Lately, I’ve just been turning on airplane mode for a few seconds and then turning it off when I’m some distance from my house.  This seems to be “fixing” the issue.

@kingRidiculous I am thinking the same thing because we have LTE phones and things started not long after the merger.  I was even told our local tower was recently upgraded when I first reported the issue (that’s when we got the cellspot at our house).  I have been very pleased with the service in our area until recently so it’s very disappointing.  I’m going to try touching base with someone at T-Mobile again about this specific issue to see if I can find anymore from them now that I know we aren’t alone.