I purchased two Teracube 2e phones and have both of them with Consumer Cellular. When I got the SIM cards for Consumer Cellular, it turned out that one of them was an AT&T card and the other was a T Mobile card. They both work but have some operational differences. I was not able to use the LTE (4G) with the AT&T card. I called Consumer Cellular and they made some changes in the Acceess Point Names settings in the mobile data. This fixed the problem.
Yeah, all AT&T MVNO’s will require manual APN setup. Has been stated several times in the forum.
Glad to hear you got your phone working.