Why does the call link not work

@hifiwizard

There are a few things to check, in that case. One is that the phone number is in the full international format:

+ country code phone number

For example, the North American style of phone number, 212-555-1212, would need to be converted to +12125551212 to give it the best chance of working, like in my Amex example.

☞ Note the removal of the dashes between groups.

In other countries, are codes often start with a 0, so this needs to be dropped. A mobile phone number in the UK might look like 07000 123456, but would need to be stored as +447000123456.

Assuming the phone number is shown as above, with only numbers and no symbols, the FaceTime app on your Mac should be able to handle it. If the phone number isn't a FaceTime number, it can route the call through your iPhone's cellular connection: Make and receive phone calls in FaceTime on Mac – Apple Support

You'll also need to check that the field containing the phone number is of the "Phone" type. If you're having trouble with a particular phone number in an item, click Edit, then "+ add more", then "Phone" and add the phone number into that new field and see if that helps.

Hopefully some combination of those things will get things working as they should.