I've currently got a setup where I'm using office 365 with adfs 3.0 authentication and DirSync. I am also utilising Exchange 2010 Hybrid to move mailboxes to Exchange Online. Everything has been working great and I now have a few mailboxes on Exchange Online and they have been working without any problems.
Yesterday, I replaced the ADFS certificate with a new one as the old certificate was coming up for expiration. This was installed without any issues and staff can log in to Office 365 and exchange online via the web and using adfs without any issues. However, since then the mailboxes that are on Exchange Online cannot be connected to via Outlook or via any email apps on iOS or android devices. The error message they all receive is:
There are problems with the security certificate for this site. The name does not match the name of the certificate.
Domain Control Validated
GlobalSign Domain Validation
CA-SHA256 - G2
Expires On: 17/04/2018
Then after you click continue, it says unable to connect to server.
Until the replacement of the ADFS certificate yesterday, accessing the mailboxes was not an issue. I would like to state that accessing the mailboxes is still possible through office 365 via the Outlook app on the web.