I can't FaceTime one specific contact.
Hello, Ginger457!
Thanks for using Apple Support Communities, it's great to have you here.
We see that you're not able to use FaceTime successfully with just one of your contacts. Does that mean that it works normally with other contacts?
If so, then it's possible something may not be working on the side of your recipient and not necessarily on your device. If FaceTime is working as expected with the rest of your contacts, then it would suggest that FaceTime and your device are not the root of the issue. We'd recommend having the contact you're referring to follow the steps in the article below:
If you can't make a FaceTime call on your iPhone, iPad, or iPod touch
We hope this does the trick for you!
Cheers.