There is one more procedure. Seems that the one I've described above works just for admin account, not for regular user's accounts.
So, try following, since this solved problem to all other computers I'm managing. We are using Windows, but I think the cause of the issue is the same no matter of OS.
My OS: Win 10 Pro x64, build 2004
My TB: v.78.4
Follow these steps by the order:
1. The most important step: Go to O365 Admin portal with your admin account and activate Advanced Security (this will automatically disable Basic Security). This operation needs probably more then 30 min. to be implemented
and active.
2. Remove your email account from TB (including message data. If you're using IMAP all will be returned back. If it's POP, then make backup before removing account).
3. Delete all Saved password from TB.
4. Update TB to the latest version (78.4).
5. Go to O365 Admin portal again and Sign-out affected user from all devices (can be done also from portal.office365.com with user's credentials)
6. At O365 Admin portal disable MFA for affected account, then re-enable it (just that, don't enforce and don't use other options)
7. Be sure that "Authenticated SMTP" is checked for the user (in applications under "Mail" tab in Active users settings. Also check all other desired options. I've checked all of them)
8. Be sure that Inbound and Outbound rules in your Firewall allows all connections for TB (I'm not sure how this goes in Linux, sorry)
9. Open Power Shell (I'm not familiar with Linux so I cannot tell how to do this in that OS :( ) and force TLS 1.1. and TLS 1.2 by following syntax:
9.1. [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls11 , then check its status by: [Net.ServicePointManager]::SecurityProtocol (the result should be "Tls11".
9.2. [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12 , then check its status by: [Net.ServicePointManager]::SecurityProtocol (the result should be "Tls12").
(even though all TLS protocols are enabled in IE for some reason I had to force it on this way because sending of emails didn't worked before I did this).
10. Set your account back in TB:
- Enter your name
- Enter your email address
- Enter your password and check "Remember password".
- Click "Continue"
- If your account was found on server, click "Manual configuration" and be sure to set following:
IMAP: outlook.office365.com; Port 993; SSL/TLS; OAuth2; your full email address as username
SMTP: smtp.office365.com; Port 587; STARTTLS; OAuth2; your full email address as username
- Click "Re-test" and if no errors click "Done".
- Login with your password and confirm 2FA.
11. Be sure that "Select one automatically" is checked under "Certificates" in TB (Tools > Options > Privacy & Security > Certificates)
12. Add microsoft.online.com; outlook.office365.com and smtp.office365.com in TB Web Exceptions (Tools > Options > Privacy & Security > Web Content > Exceptions). Also check "Accept cookies from websites" and select "Always" for "Accept third-party cookies".
12. Subscribe desired folders under newly re-created account and restart TB.
13. Open each subscribed folder to connect them and check do you see all your emails.
14. Try to send email. If not work, wait some time and retry. MS needs some time to implement steps 1, 5 and 7.
Note: Seems that MS was changed something related to Basic and Advanced security, so OAuth2 stopped to work with Basic security.
I hope this will solve your problem as it happened in my case. TB now work like a charm :)
