cellular data doesnt work on ios 14.5 anymore!

I've had a trouble ticket opened for four days since this past Friday.  Hopefully they have an engineer working on it. It's easy to blame Apple on this one because it started happening after the iOS 14.5 upgrade, but I strongly suspect this is a problem with T-Mobile:

• It's only happening with No Credit Check plan customers. Customers who have switched plans or swapped SIMs to other plans immediately have their phone work
• For most customers forcing LTE does not work, however for a few it does
• The error in the browser is Domain=NSURLErrorDomain Code=-1001 "The request timed out."

All of this together leads me to believe that T Mobile has some kind of incorrect network configuration issue. Although the phone appears to have signal and connectivity, it's acting as if the cellular network is denying traffic. 
If this truly were a problem with iOS, it would happen for all 5G customers and across multiple carriers. You would be hearing about it a lot more.

I have been through 3 rounds with T Mobile and have been waiting for "Shelly" from Tech support to call me back for several days. I am not happy.

I have been having this problem since 4/28 and reached out to Apple directly on 4/29. After 3 subsequent visits to the Apple Store WTC in NYC and a number of "genius'" being involved they confirmed un-officially that the problem is with iOS 14.5 and 14.5.1 and as far as I'm aware 14.5.2. In the store they had me backup my original iPhone 12 to my MacBook prior to their resetting it to discover that the problem was real and I'm not crazy. Switched to a new phone, same problem. I've of the reps moved my SIM card to a 12 Pro and it worked, but that demo phone was evidently "not" running iOS 14.5. After more calls to Apple they agreed to swap out my phone and I would pay the cost difference. Got to the store and nobody knew anything. They ended up comping the difference in cost but the 12 pro max has the same "no cellular data" problem. They swapped out another phone and didn't do the upgrade to 14.5.1 and all works fine like it did before the update, but my backup taken when my original phone was using 14.5 cannot be restored. I'm screwed and Apple could not care less. I can live without things in the backup until fixes are made that allows for the restore. This weekend I purchased a new Apple Watch 6 and I'll be damned but it wants a version of iOS higher than 14.4.2 in order to initialize and set up the watch. It's unbelievable that Apple can issue such an advertised major upgrade without sufficient testing of such a big ticket item with a major carrier and then be so apathetic in regards to a fix. I've got an Apple Store appointment now to find a work around using a demo phone at the store to initialize the watch. Hopefully some solution will work, but at this point I have little confidence in Apple and finally admit it's time to migrate to Android. High prices shouldn't come with hassles.

Same problem here. NCC account, upgraded to iOS 14.5.1 and data stopped. Fix for me was migrating my account to Magenta 55+.

This is still not solved. Dunno how this can be marked as solved…

Jass, They would not tell me. She said she made "some" adjustments on her end. I did it by Chat so I could work on my phone while working with the rep. Several times I had to hard rest my phone. Good luck.

Sta2lt what was the solution as I am experiencing the same issue. And submitted a trouble ticket over a week ago. 

I took Mike’s advice and chated with a rep who was able to step me through fixing the problem.

Same issue. No credit check plan. iPhone 12 mini. Updated to iOS 14.5.1 and broke cellular data. Oddly, Ookla Speedtest app works, but no other apps can access internet over cellular. Did all the things, including a factory reset. No success.