"We can’t show MailTips right now" warning in Outlook in Microsoft Office 365 Dedicated/ITAR (vNext)


In Microsoft Outlook in Microsoft Office 365 dedicated/ITAR (vNext), you receive a "We can’t show MailTips right now" warning after you change the From address to the address of a non-mailbox-enabled recipient.

Screen shot of the warning page

However, in Microsoft Outlook Web App (OWA), you don't see this warning. Instead, OWA displays a MailTip from the current forest.


This behavior is by design.

More Information

The attempt to complete a MailTips lookup fails if the From address that you specify isn’t associated with a mailbox in the current user’s forest when you use Outlook. The MailTips tries to complete the lookup under the security context of the user in the From address. The attempt fails if the recipient isn’t a mailbox user in the current forest.

For example, if the address is associated with a distribution group or a mail user, you receive the following error message in the Outlook logs: 

The ActingAs parameter does not match a user in the directory.

MailTips from the current forest are displayed in OWA.

Article ID: 3083843 - Last Review: Aug 4, 2015 - Revision: 1