Server says [AUTHENTICATIONFAILED] Authentication failed

The above is the exact error message that I’m receiving trying to login (initial setup and then after when hitting send/receive) using version 6 on a Windows 8.1 tablet and entering my microsoft office 365 account using my custom domain name. I’ve tried this (which works using any Outlook client), my onmicrosoft account name which I no longer use to login and neither works. What ends up happening is an IMAP and smtp setup and attempt to use the diagnose button doesn’t help as I am repeatedly prompted for a password. Then I get “Your credentials were rejected.” Using the stock mail app and adding an account, my custom email address and password worked flawlessly.

Hi, I will need your SMTP and IMAP logs, go to tools - settings - advanced, check SMTP and IMAP under your account, apply and restart eM Client.

Try to authenticate with server and after that send logs to together with this topic’s URL in subject.

then you can turn logging off.