Challenge : Outlook would connect to one MS365 mailbox but then started constantly flashing for authentication for the disconnected Hotmail mailbox, but the credentials window disappears before being able to click on the box to enter a password.
Cause : Unknown ? Clash of accounts? Glitch in the Matrix?
Solution : More of a workaround solution.
- Close Outlook
- Open Word > Create a blank document
File > Account > Sign Out
- Then click sign in, Username and Password prompts. Log in and authenticate.
- Close Word
- Open Outlook and everything worked as normal.