My Organization is having problems opening AIP labeled emails in Outlook 2019. They are getting the email and it is asking them to verify the information, but that's as far as it goes. Trying to double click on the email only gives the "You don't have the permissions" window. This still will not bring up a prompt for them to verify.
I checked my labels. I set the whole domain for viewer permissions and it is properly applied through Policies. Is there something I'm missing? Does the domain need to be added to my AAD or is there a problem with Outlook?
I sent the same email to my school account. It opened with no problem.