Thunderbird 91.0.3 Error: "Sending of the message failed"

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Joined: September 1st, 2021, 9:19 pm

Post Posted September 1st, 2021, 9:48 pm

I just installed Thunderbird 91.0.3 over my old Thunderbird (78-something) on a Windows 10 computer through a standard xfinity account. I use Avast free antivirus and windows' built-in firewall. Outgoing server:, port 465.

It's working fine, but whenever I open it with my main Profile (a basic gmail account), I get three messages consecutively saying "Sending of the message failed" - even though no message is pending to send. When I have cleared those error messages, everything seems to work fine, including sending and downloading messages. If I close Thunderbird and then reopen it, the same thing happens again. BUT it does NOT happen in either of two other profiles (also gmail accounts). Note: this was NOT happening on Thunderbird 78, and only started after I installed 91.

Can anyone suggest a way of stopping this?


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Post Posted September 2nd, 2021, 3:24 am

Moving to Thunderbird Support as no specific bug has yet been identified here and this seems to be a profile specific problem.

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Post Posted September 3rd, 2021, 9:40 pm

Folks, please help me. Every time I open firefox - IN ONE PARTICULAR PROFILE ONLY! - I get a string of four notices saying "Sending of the message failed". Each message has to be cleared one at a time, in order to continue, but after that, the warnings have no effect: I'm still able to send and receive messages without any other issues. I have three other profiles in Thunderbird, and none of them has this problem.

ALSO, I have upgraded Thunderbird from 78 to 91.0.3 on three different computers, and this problem occurs in this particular profile on all three computers. Therefore, I'm guessing that the problem has to do with some corrupted file(s) in that particular profile on all three computers. (Note that the problem only occurred after upgrading from version 78 to version 91. Before doing that, I never had any issues of this sort.)

Please advise...


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Post Posted September 3rd, 2021, 10:20 pm

Is "Sending of the message failed" the full message?

Any stray messages in Outbox under Local Folder?

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Post Posted September 3rd, 2021, 10:41 pm

i would have a look at your Firewall Rules, might not have allowed access to it with the update to TB91

or try a Test Profile in Thunderbird91 an see if you still have the Message Failed sent error

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Post Posted September 5th, 2021, 9:29 pm

Friends, thanks for your replies.

wsmwk, "Sending of the message failed" is the full message - no clues as to what it refers to. I will see if there are any stray messages in Outbox of Local folder.

Snake4, I will look to see what firewall rules might apply (I'm using only the built-in Windows 10 firewall - nothing fancy). I have been thinking about building a new profile for the same email account that's causing the problem. May give that a try. One clue is that I have 3 other profiles for 3 other gmail accounts, and none of them is having the same issue.

Thanks again!

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Joined: September 1st, 2021, 9:19 pm

Post Posted September 5th, 2021, 9:33 pm

FANTASTIC NEWS! wsmwk, I checked in Outbox of Local folder, and there were ancient emails that somehow had never been processed (the newest from 2014). I deleted them and... voila! No more warnings - problem solved! What a simple solution to a very annoying problem. I can't thank you enough! I hope someone else having a similar problem sees this message thread!

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