Credential Manager - remove bad credentials
This is often required when Outlook does not ask to login and a mailbox can not be accessed.
1. Close Outlook
2. Open Credential Manager
3. Search "cred" in the Task Bar search and click on "Credential Manager"
4. Remove all entries appropriate to the issue. See circled example below.
5. Open Outlook again.
6. Enter the login details for the Mailbox when prompted.