When running a hybrid environment we have noticed that in some situations that an user with an on premise mailbox is not showing in the Office 365 GAL.
After comparing account details we noticed that the attribute CloudExchangeRecipientDisplayType was empty for those accounts.
In a search how to fix this we found an article indicating the following:
Make a note of the current value’s
In the On-Premise AD manually set the following attributes:
Then replicate this information to Azure Active Directory. Once this replicated to 365, check the CloudExchangeRecipientDisplayType attibute to confirm that this attribute now has a value. Then set the attributes in the on premise user object back to their original values.
I hope this was informative. For questions or comments you can always give a reaction in the comment section or contact me: