We have moved all our mailboxes to Exchange 2013 from 2010 and everything except MailTips seems to be working fine. Outlook 2013 clients within the internal network and OWA display MailTips fine, but when an Outlook user connects from an external network the "We can't show MailTips right now." message displays. Here is what I've tried so far:
- Running the EWS test from testexchangeconnectivity.com comes back with no errors.
- Setting OOF from Outlook externally works fine.
- I've verified that the External EWS URL is set correctly on the Vdir.
- Running an Autoconfigure test from Outlook returns the External EWS URL.
- Windows Authentication and Anonymous Authentication are set on the EWS Vdir. I've tried turning Basic Authentication on and off again without any change in behavior.
- I've recreated a user's Outlook profile.
What am I missing here? I feel like I've covered all the basic troubleshooting steps and I know EWS is working since I can set OOF.