iPhone iMessage not working

I’m at my wits end here. My iPhone all of a sudden iMessage stopped working on. It would start to send as an iMessage then fail right away with the red ! and send as a text message. I have tried the following:

1. Turn off iMessage and turn back on (it does activate fine)
2. Turn off iMessage, reboot phone, and turn back on
3. Verified the phone number is checked inside of iMessage
4. Sign out of iCloud and sign back in
5. Checked date and time
6. Performed reset of iPhone (not factory reset, reset all settings reset)
7. Installed any iOS updates (Running 17.6)

I’ve googled and tried everything I can find but nothing. If someone sends the phone a text using iMessage it comes through as an iMessage, but as soon as I reply, it fails and goes into a text message

Anyone have any other ideas?