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How do I get Thunderbird to connect to a properly-configured Office 365 mail account after shutting down and then restarting the client?

  • 3 replies
  • 65 have this problem
  • Last reply by milchsage

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I get my Office 365 account set up and working in Thunderbird. I can download and send mail just fine using the auto-detect or manual account settings recommended by Microsoft/Outlook/Office 365. Everything appears to be working as it should as long as the client stays open. When I shut the Thunderbird client down and restart it, it can no longer access the Office 365 mail account. I get a popup error message:

The current operation on 'Inbox' did not succeed. The mail server for account (my Office 365 account) responded: User is authenticated but not connected.

It has no problem connecting to Hotmail, Gmail and other email services, and I can access Office 365 through the web client, but Thunderbird refuses to connect. If I remove the account and re-add it, I can have full access to my email again, but only as long as Thunderbird stays open. If the client gets restarted, it's gone again.

How do I fix this?

All Replies (3)

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I'm having the same problem, on (at least) two different computers. It's clearly a new problem--this account worked fine with Thunderbird until a day or two ago. And it's clearly a Thunderbird problem--I can still access the account just fine through Outlook. So what on earth is happening, and how do we fix it?

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I think you might be having a cached password problem. I was having it and was able to resolve by deleting my stored password in Thunderbird. I referenced and also posted my question and resolution:

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It's solved here:

You need to open both ports (587 and 993) for inbound AND outbound on your firewall.