iPhone 13 messaging issues

I just got a new iPhone 13 and for some reason I can receive text messages from android phones but not send them. This is a client that I frequently send many messages a day to until I got this new phone. I looked it up and followed all of the troubleshooting issues from Apple, AT&T and many other websites to no avail. I have turned my messaging on and off, airplane mode, wifi, SMS/MMS settings, restarted my phone many times and taking this person‘s contact out and re-entered it all again. I cannot figure out what the problem is. So far this is the only contact I can tell that I’m having this issue with. We even went so far to troubleshoot on his phone to make sure I wasn’t blocked or if there wasn’t something going on with his end. Ideas?