Outlook
A Microsoft application for managing email, calendars, contacts, and tasks across devices and platforms.
"user is authenticated but not connected" when connecting to Outlook Office365 from Thunderbird via IMAP and OAuth2
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(54.400000000000006, 93%, 15%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EFK%3C/text%3E%3C/svg%3E)
Filip Kurowski
5
Reputation points
When connecting to Outlook Office365 from Thunderbird via IMAP and OAuth2 I get the reply "user is authenticated but not connected". Every now and then it works, but just like 30% of time ... Why and how to repair this?
Thanks in advance for any suggestions!
Outlook
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![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(220.8, 45%, 31%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EKS%3C/text%3E%3C/svg%3E)
Ken S 0 Reputation points2025-12-06T04:51:07.8133333+00:00 Same issue. It worked all the time until I had to reinstall windows and Thunderbird. It wont get any emails from Hotmail account. May have to use Thunderbird for Gmail and Outlook for Hotmail.
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Filip Kurowski 5 Reputation points
2025-12-08T10:37:49.7566667+00:00 Don't tell me that I have to use 2 mail clients just because of Microsoft e-mails (office365 or hotmail) are working just with Outlook - is this even legal?!? :-/
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![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(99.2, 14.000000000000002%, 19%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EKS%3C/text%3E%3C/svg%3E)
Ken S 0 Reputation points2025-12-08T21:40:19.7733333+00:00 Not sure if it will fix the random failure but I fixed mine by logging into Microsoft and going to the security tab. From there, make sure two factor authentication is on. You then are able to set up an App password. Once that is done it should fix the issue.
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Filip Kurowski 5 Reputation points
2025-12-09T10:59:37.4866667+00:00 The password option I have allowed but still I get connected just sometimes ... No idea what it depends on if I connect or not, once per 30 clicks I get in :-/
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