There was a solution that I suggested in this thread that worked for others, maybe it will for you as well? https://productioncommunity.publicmobile.ca/t5/Get-Support/Re-OnePlus-11-5G-MMS-messages/m-p/1155783/highlight/true#M806354
I can also confirm that I cannot send / received MMS on the OnePlus 11G. Can't say exactly when it started since I don't use MMS that often, but I noticed it a few days ago. I had updated the APN settings a while back, and it was working, at least up...
