Thunderbird-Hilfeforum

I've been a faithful Thunderbird user since the beginning - and continue to use Thunderbird with our company's Microsoft365 deployment

until Monday of this week -- when suddenly I find that my credentials are being refused.

The symptoms

• XXX: Connected to outlook.office365.com
• nothing in the activity viewer
• no email coming in

I've read and tried all the fixes proposed in the article at https://support.mozilla.org/en-US/kb/microsoft-oauth-authentication-and-thunderbird-202 (restarting thunderbird after each step, naturally)

• have authorized Thunderbird to our Microsoft365 tenant
• created and tried registering with a new thunderbird profile
• have set my security settings to 'accept all cookies'
• have used the config editor to remove 'oauth2.issuer' and 'oauth2.scope' values
• I've checked that my account in Microsoft365 has IMAP and Authenticated SMTP enabled

So, since Monday, I've been living in hell, trying to pretend that the Microsoft Outlook app for macOS is useable, but it's practically debilitating to be forced to use that piece of software.

Can somebody please point me to another possible set of steps that I can use to try and diagnose this?

I absolutely hate myself for having to ask for help on this, but I'm at my wit's end...

I have connected my wifes outlook acc. and my Gmail acc. without issue, one on each of the user profiles, but with the 3rd my Outlook acc, I keep getting the "Unable to log in at server..." error. The Name/email/password are all correct. I have tried connecting my 3rd email account (+New/Existing Mail Account) as the 2nd account on different profiles but I get the same error trying to connect my Outlook acc.. I have verified that Thunderbird is configured to accept cookies. Is there some issue with having 2 outlook accounts linked to the same instance of Thunderbird?? (I hope not!! - that would be a complete deal-breaker!) Is there anything else I can try? Many thanks