
POP3 Connection to MS365
I am having a problem receiving messages today in my Thunderbird email account from MS365. The message reads - The RETR command did not succeed. Error retrieving a message. Mail server outlook.office365.com responded: Server Unavailabble. 21
I did delete all messages from all my folders in the email account to see if it was a particular message that was stuck. My email account has 5GB of empty space currently. Did Microsoft make some changes? Any solutions
Maria
Vsi odgovori (1)
I ran into the same issue today with Thunderbird and my Office 365 account — exact same RETR error. It looks like it might be a temporary issue on Microsoft's side. I checked the Office 365 service status page and there was a mention of intermittent mail delivery issues earlier.
In the meantime, try switching from POP to IMAP if you're still using POP3 — that might help bypass the RETR command altogether. Also, restarting Thunderbird in Safe Mode (Help > Troubleshoot Mode) helped me rule out add-on issues.
Let’s hope Microsoft resolves it soon if it’s on their end!