I keep trying to facetime someone and I get a notification that says this person cannot be reached on facetime at this number check contact card. what do i do to fix this?

Hi, I had this issue as well.

I tried 3 things, and I'm not sure if it was a combination of 1 or all 3.

1. Turned phone on/off - full restart fixes more problems then anything else.
2. Deleted the contact card and added it back in with the same exact information.
3. Turned Facetime off > then back on.
   1. To do this - Go into Settings, Scroll down and find "FaceTime" and select it.
   2. Select the green indicator next to "FaceTime" - once off, and then right back on.

Item number 3 is what solved my issue. Hopefully it resolves yours as well.

Maybe related since a brand new iPhone 13 with the (lat/new)est iOS v15 shows "Choose Another Phone Number or Email Address to Call...". Never had this problem in the old iPhone 6 + before it. Both use VZW.