If you have come across this lovely message then you are at the right place. This was thrown up from Outlook with an Office 365 account. The following symptoms were present:

-You will need the internet for this 
-Outlook kept reporting "Trying to connect".
-Microsoft Edge wasn't able to browse to any websites at all. Chrome and any other browser was fine. 

You can check Outlook by Ctrl+Alt+right clicking Outlook's tray icon and selecting the test account option. Punch in you email and password - you'll get the above pop up error.

Here is a list of things you can try, in no particular order (although #1 sorted it for me in my case):

1. Create if not present or change of there the following regkey:


Set to 20 hex (DWORD) - implies favour IPV4 over 6.

(00 can also be tried) - IPV6 disabled.


2. Clear all MS related credentials from the credential manager (search inside the classic control panel)


3. Access the following registry path


Add a new entry of type REG_DWORD with the name EnableADAL with value 0

Remove the DisableADALatopWAMOverride entry if it exists.



4.  Shut down all Office Apps

In Explorer, navigate to  C:\Users\%Username%\AppData\Local\Packages\


Delete the Keys in the folder

Relaunch Outlook - Keys are re-created automatically.


5. Add the AAD broker plugins to the loopback exemption manager (yeah I know..)




For fun you can reference this MS article as well: 


Reboot after making registry changes. I had to create a new Outlook profile as well.