You might have been searching for a solution on the web and we have done that as well as we are facing the same problems as what you do. The error “buddy_phone_not_ar_capable_desc” is slowly spreading like wildfire among Pokemon Go players. Are there ways to resolve this problem or even prevent it? Yes!
This morning, we had a response from the Niantic team that the bug has been addressed and that they are working to resolve this as soon as possible. In the meantime, we strongly suggest that you don’t update your Pokemon Go app unless you won’t mind that you would be unable to play with your buddy as well to obtain its gifts. They also stated that we should keep an eye on their bug list of known issues, but the link that they provided seems invalid, as it does not exist any more.
For those that are already affected, there is nothing much else than waiting for the fix that’s been cooked at the Niantic’s kitchen by the master chefs. In the meantime, we can enjoy this weekend with their latest Pokemon Go event. Have you already spotted Zarude or have you already caught one? Good luck this weekend Trainers!