Outlook keeps asking for password… Using Office 365 but on-premise exchange?

Starting in Outlook 2016 version 16.0.6741.2017, Microsoft has enabled a new feature called Direct Connect to Office 365. What this feature does is connect Outlook directly to Office 365 if Autodiscover is not working. This is great feature but a network hiccup may cause your mailbox to connect to Office 365 rather than your on premise Exchange, even with a valid autodiscover record.

For Direct Connect to take effect the user must have an active mailbox on Office 365 with a valid license. Typically Direct Connect would be a neat feature unles you are in the middle of a migration to 365, but a network hiccup could incorrectly connect you to 365 even though you havent completed your migration yet.

During 365 migrations deom Hosted Exchange or On-Premise, we recommend disabling this option from the user computer registry:

You can stop Outlook from checking Office 365 for settings by setting a registry key.

DWORD: ExcludeExplicitO365Endpoint
Value = 1

Then restart your computer and it should stop trying to connect to Office 365. When you are ready to flip the switch on your migration, remove this registry key.

Heres a great article describing the whole thing in more detail…

Outlook won’t accept “app password” after setting up MFA

So we use Exchange Online Plan 1 and Outlook 2016. After setting up Multi-factor Authentication for one of my email accounts I found that after a couple of days Outlook started popping up the password prompt for the account.

No matter how many times I tried it wouldn’t accept the “app password” i created here or the normal password for the account. After a bit of digging I found this article which suggested adding the following registry key which solved the problem for me.

dword value 1