Huh.. I don’t know why the XBee would entirely stop responding. Does it still respond on XCTU? Could you have accidentally put it to sleep?
So far I have not managed to get my LTE-M XBee to connect to the internet with Hologram’s sims. I get denied service every time; sometimes quickly, sometimes after hanging at “22” (searching) for a long time. I’m having the same issue whether it’s on a Mayfly, connected to a PC and talking to XCTU, or connected to a PC and using a terminal with the USB direct access pins at AT commands.
The same hologram sim works fine in a 3G XBee and my LTE-M XBee can connect to the network just fine when I put in my AT&T sim from my cell phone. But I cannot get the hologram sim to allow connection with my LTE XBee.