We have this on our boat and everything was working great until this afternoon. We switched from generator to shore power and now it will not obtain IP Address for the AT&T sim card. I know that we have AT&T service as our phones have LTE service. I am also able to log into and connect it via the personal hotspot on my phone and the wifi at the marina. However we need it to connect to the AT&T sim that we use the majority of the time. I have not changed any of the settings so not sure why it stopped working.
This is many possibilities - data plan of the SIM, outdated firmware or etc. Please test the affected SIM card with another device to narrow down the problem. Ensure the device is running with latest firmware version.
Updated the firmware however we had the 6.3.0 and now updated to the 6.3.3 version but no luck. I think it may be on AT&T at this point as I tested my Tmobile sim card and it connected right away.