If you can’t make calls in FaceTime on Mac
If you have trouble making calls in FaceTime, see the suggestions below.
If you can’t call a specific person in FaceTime
You may need to choose a different way to call. When a person’s name is blue, they have an Apple ID and you can reach them directly on FaceTime. When a person’s name is green, you can click “Invite with Messages” to send them a text message with a link. When a person’s name is red, that contact cannot be reached by Messages. You should instead create a link to a FaceTime call, then share the link with them.
If you’re restricted to calls with only certain people, an hourglass icon
If you can’t make a phone call in FaceTime
Make sure you’ve set up your iPhone and FaceTime on Mac for phone calls.
Make sure your iPhone is connected to the same Wi-Fi network as your Mac (or set up Wi-Fi calling, if available).