@RogerMurdock Yes - I (too) had a similar experience and discovered it boiled down to the way T-Mobile sets up services/devices. The work around that I took was to "ask" for their home cellular gateway appliance and unlimited service. Once I established the T-Life mobile app requiring me to confirm the 6-digit passcode to the home cellular device and service worked on their hardware...I turned off the device and pulled the SIM card. Their home cellular gateway was at NO additional charge. The SIM was put into the MG51 and works as planned - you might have to add your MG IMEI to the plan for the device to work.
Probably not the most ideal way to proceed but it got me over the hump per se with establishing T-Mobile service since I wasn't a T-Mobile customer prior to receiving the MG51.
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