Forum Discussion
outlook 2010 and 2013 continually asks for password in hybrid environment
pazzoide76 So it all came down to MFA via Security Defaults? That's not the first time I've heard it as I now recall another conversation with a similar issue, not identical, where I actually suggested that. It didn't struck me as a solution this time and I can only blame my six weeks vacation..
harveer singh Good job!
pazzoide76 Please mark the above reply with the solution as "Best response" for future reference.
pazzoide76 Hello, in addition to the previous suggestions (Modern Authentication/ADAL). Try using the ExcludeExplicitO365Endpoint registry key during the migration (and then remove it).
Exclude initial check to Office 365 Autodiscover URL
Registry Hive HKEY_CURRENT_USER
Registry Path software\policies\microsoft\office\16.0\outlook\autodiscover
Value Name excludeexplicito365endpoint
Value Type REG_DWORD
Default Value 0
True Value 1
False Value 0
The problem manifests itself with users migrated to exchange online (keep asking for login).
With users in the on-premises exchange everything works fine.
Anyway I tried the registry key but it keeps asking for the login.
I repeat that over the weekend I configured a mirror environment (in the test environment I did not enable https://docs.microsoft.com/en-us/exchange/configure-oauth-authentication-between-exchange-and-exchange-online-organizations-exchange-2013-help?redirectedfrom=MSDN) and outlook 2010 and 2013 clients work.
I repeat the two environments are the same changes only OAuthauthentication between Exchange and Exchange Online organizations.pazzoide76 Ah, I understand. Could it be an incorrect autodiscover entry in the migrated mailbox that's causing this? Let me see if I can find an article describing this behavior.
If it was a badly configured autodiscover problem, why do Outlook 2016 clients work?
The problem occurs with all migrated mailboxes
