Freron MailMate

My Outlook account stopped syncing. I upgraded and downgraded a few times but was getting different errors.

1. On the latest beta, I was getting errors saying IMAP password is wrong, even after entering the correct password, which was weird since I used to login with OAuth earlier and approve the MailMate app to access stuff, not enter a password.
   
2. Then I downgraded to the last public release, here it opened a browser window to approve MailMate but it did so multiple times.
   
3. Upgraded to 6065.
   
4. I tried adding the account again as a new IMAP source and saw in the settings & MS documentation that IMAP server has changed from imap-mail.outlook.com to outlook.office365.com, so I updated my existing source with this, the new IMAP source hadn't started showing any emails yet, not sure if it would've succeeded sicne the IMAP/SMTP settings were identical, so I removed it.
   
5. After updating the IMAP URL, now it didn't ask me for a password and opened the browser window to approve MailMate as an app like earlier but it's doing this again & again in a loop and it finally stops and takes the account offline. I was keeping an eye on Keychain Access and the 3 items (token, refresh token, expiry) keep getting created & removed when I'm approving the app in the browser window.

Also I don't remember for sure but the tokens in Keychain Access were named with "outlook" in the middle, I deleted them sometime after (3), but the new tokens are named with "office365".

Did something change recently wrt Outlook accounts ?