I have Outlook for Mac connected to an on-premises exchange account, and I keep getting this error:
"Mail could not be received at this time". The server for account "" returned the error "Logon failure: unknown user name or bad password.". Your username/password or security settings may be incorrect. Would you like to try re-entering your password?
I can reenter the password and it will force the mail to download (or to send), but it constantly prompts me with this error. I've done some research on this issue and I've deleted keys from Keychain access and I have also tried removing the account and readded it. I have tried using different credentials and configuring the account manually. It occurs on both of my macs. I can use the account successfully from Windows 10 or from Outlook on iOS.
This issue is quite annoying and it has prevented me from seeing E-mails in a timely manner.
I'm in Office Insider Fast Ring build 181029. However, it happens in the normal ring and it has been happening for months. Office 365 is licensed through another unrelated tenant to this account.