Update to my post - procured a new SIM, still cant get connected and tried basically every step in the troubleshooting guide. Seeing this with at!gstatus?:

at!gstatus?
!GSTATUS:
Current Time: 386 Temperature: 36
Reset Counter: 1 Mode: ONLINE
System mode: WCDMA PS state: Attached
WCDMA band ...

Ugh - was afraid of that. Of course now I'm having trouble getting in touch with Nomad to cancel my subscription and/or get a new SIM. Thanks for your reply!

Hi all,

Need some help troubleshooting my MC7455... Used this for about 2 months on AT&T with no issues and now suddenly I can't connect.. Here's what I see when running that at!gstatus? command

at!gstatus?
!GSTATUS:
Current Time: 585 Temperature: 39
Reset Counter: 1 Mode: ONLINE
System mode ...