Forum Discussion
Solved
Exchange hybrid - Users with on-prem mailboxes are being considered 'unauthenticated'
Overview + Setup Information This issue relates to Exchange, SharePoint Online and Office 365. Here's a quick summary of our setup: We've integrated our on-prem AD with Azure AD via Azure AD...
Moreover those messages are sent from the SPO backend, so Exchange is not even involved. Have you tried allowing just the no-reply@sharepointonline.com address?
The quick answer is...you can't. Exchange Online users are not authenticated on premise, the email originates from Exchange online which is essentially a federated organisation. Maybe MS could implement a separate tick box for "federated partners" but this is unlikely to happen.
Moreover those messages are sent from the SPO backend, so Exchange is not even involved. Have you tried allowing just the no-reply@sharepointonline.com address?