We have just integrated InTune with Apple Business Manager and turned on the domain Federation which now allows our Azure AD users to log into Apple Devices with their work email address. We have hit an issue with this in that the users can no longer download apps from the App Store, or through the InTune Company portal. The users are presented with a message 'This Apple ID can't be used to make purchases'.
Hoping to get some assistance on this one. The main annoyance here is that the Company Portal cannot be downloaded from the app store without using a personal Apple ID. The secondary annoyance is that once the company portal is installed and the device is enrolled the apps configured through InTune also fail.