I am unable to add Outlook account for an on-premises mailbox for in a Hybrid Office 365 solution.
Mail flow works just fine. The autodiscover records are pointing towards Office365 and all of the domain checks are green. It is only when I try to add an Outlook account the search hangs with "An encrypted connection to your mail services is not available"
This is true when adding the mailbox both from inside and outside our network organisation.
I'be been searching this on google, and everywhere I can find only problems relating to adding a migrated mailbox to Office 365, and this problem that I have is just the opposite.
Please advice, I am going desperate.
Edit: I also tried to use the MS Remote Connectivity Analyzer. The last error that I have is:
We were unable to get account settings after a domain redirection.
The problem was that the outlook autodiscover records must point to the on-premises exchange server until the very last user is migrated from it. The on-premises exchange server is doing the autodiscover redirection, for mailboxes that are in the O365 Cloud.
The confusion that happened is that O365 gives a warning that the DNS records are incorrect. That is why my autodiscover was pointing to O365. I thought that O365 servers will do the redirection for the on-premises mailboxes. I was wrong.