How do I recieve MMS messages in Spacebar with AT&T/ATT?

I have KDE's Spacebar installed on my Librem 5 but cannot figure out how to access/receive MMS messages. (edited image example) I added my MMS settings but still get the message above: Have any of you been able to receive MMS messages? I am attempting to receive cat photos. The screenshot was taken on Mobian. **Edit**: I am using AT&T (sometimes refered to as ATT) but would prefer a carrier-independent solution so that other may recieve help here as well