This started on one family member’s V30 yesterday and another today.
This affects more than one LG model.
Obviously T-mobile has changed something in the network.
See this thread here:
I have tried safe-mode, Disabling mobile data. Etc, etc. including all suggested on the internet and above thread with no success.
I would advise against making any changes until an official response is issued from someone with sufficient knowledge to understand what network-wide changes were made and explain how to correct the problem or how T-mobile intends to correct the problem.
I worked this issue for more than 8 hours today!