Can't connect to one of my contacts

I have a new iPhone 13. I have found that when I try to call one of my contacts, I get a message about my call not being accepted. I reported this to the contact and they checked with their carrier and found that it's not them. I tried using my wife's Android phone and had no problem completing my call. I can't see anything in my settings that might be causing this. Has anyone got an idea what might be causing my problem?