Hopefully I can save at least one person from wasting an hour or more of their time trying to figure out what’s going wrong when all your code seems correct. Make sure the contact selected as the suspect actually has a phone number listed in the contacts. I had selected my own contact to avoid accidentally calling anyone, which I didn’t realize only had my e-mail address listed and not a phone number.
I’m sure there’s some way to check that, but I haven’t done that research yet.