Nighthawk M5 (MR5200) Loses Connection

[JonMcKinney]

I purchased the M5 and have a T-Mobile 5G data plan.  I got it so that I could use a stronger antenna and have an ethernet port when on the road for work.  For the first month, the device worked great.  Then, the connection would not remain stable between my Microsoft Surface and the mobile hotspot. 

The mobile connection itself is stable and has good strength, although sometimes it starts giving messages to update the APN, when it does not need updated.  Once connected, the cellular data only makes it to my Surface by WiFi for a minute or so before the connection is gone, and I have to restart/disconnect/reconnect again.  At first, I had to do this a few times a day, but now the device is not functional.  

I went to T-Mobile and they confirmed that my connection and SIM card are fine.  They gave me a new SIM to try, but same issue.  I have tried factory reset.  

[JonMcKinney]

I should add, we have one of these for home internet and it works no issues.

Also, I have tried connecting by ethernet and also no data to Surface, even though cellular network connection is fine.