Hello!
Looking for some troubleshooting help, I have been using GrapheneOS successfully with AT&T prepaid for a few months now. As of yesterday or today, it appears I have stopped receiving SMS at all. For calls, it seems only when not connected to WIFI. With wifi on, it shows I have bars but says "No Connection". If I turn wifi off, the cellular connection icon turns to the classic no signal with an exclamation point. When connected to wifi, I can use wifi calling and RCS. Any thoughts on troubleshooting steps? Thanks!!

Maybe your local towers were updated? Have you tried resetting your mobile network settings or contacting AT&T?

Thanks for your quick response! I tried resetting, and also called ATT when I got a chance, they recommended stoppong in to swap the physical SIM out for an eSIM. Did that, it didn't initially work. Restarted the phone, didn't work until I went into the SIM settings and reset the APN settings. Seems the main issue was the SIM card. Thanks again!