I was about to make a new thread here before I saw this post. I installed a T-Mobile sim card in my Dasaita about 2 months ago, and I was always able to reliably connect to the Internet until a few days ago when I got my vehicle back from a body shop.
I took my truck to a body shop to upgrade the sound system, and I noticed the day after getting my vehicle back that I was unable to connect to the Internet until I rebooted my Dasaita through the factory settings. For the rest of that day I had no issues with my LTE connectivity.
The following day when I started my car I noticed there was an exclamation mark on my LTE bars notification at the top and I was again unable to connect to the Internet. Except this time rebooting the device didn't fix it, neither did relocating my vehicle to another area. It just simply wouldn't connect anymore.
The day after that, after starting my vehicle in the morning, my Dasaita was now completely unable to detect my SIM card, and the "SIMs" section under Network & Internet was grayed out. After popping out the Dasaita, pulling out the SIM card reader and pushing it back in, and then restarting the device, it was able to detect the SIM card again, but still no connectivity.
The following day when I started my vehicle it was again unable to detect my SIM card. I have not had any LTE connection ever since that first day after receiving my vehicle from the auto shop, despite T-Mobile confirming that my SIM card was still active.
At first I thought maybe because the body shop had re-ran the cables for my 4G antenna and GPS antenna through the interior dashboard that maybe the antenna cables had become damaged or snagged, but after gently pulling on both ends of the antenna cable with the Dasaita popped out, it moved very easily and freely.