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Thunderbird: Error - "Sending of Message Failed"

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Have used Thunderbird for years with no problems. But in the last month or so, when sending a message that contains forwarded content or contains an email link, the Error Message occurs - see following:

"Sending of the message failed.

The message could not be sent using Outgoing server (SMTP) mail.btinternet.com for an unknown reason. Please verify that your Outgoing server (SMTP) settings are correct and try again."

However, if the email link or forwarded content is removed the message sends ok.

The SMTP server settings have never been changed but have tried some of the suggested ideas in the Help pages (changing ports, removing cookies etc) to no avail.

This happens on two separate PCs with different Anti-virus systems.


Any ideas gratefully received.

Have used Thunderbird for years with no problems. But in the last month or so, when sending a message that contains forwarded content or contains an email link, the Error Message occurs - see following: "Sending of the message failed. The message could not be sent using Outgoing server (SMTP) mail.btinternet.com for an unknown reason. Please verify that your Outgoing server (SMTP) settings are correct and try again." However, if the email link or forwarded content is removed the message sends ok. The SMTP server settings have never been changed but have tried some of the suggested ideas in the Help pages (changing ports, removing cookies etc) to no avail. This happens on two separate PCs with different Anti-virus systems. Any ideas gratefully received.

All Replies (2)

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Hello there hooch. We haverveld your message. We try to help you.


the content of your messages to be sent only contains only a url or references to an Internet address or email-links. with this one it will not be sent because both are present.


What kind of computer do you have? Can you send me from both from the computers the Smtp setting s that recent now.

https://support.mozilla.org/en-US/kb/cannot-send-messages

Greetings Firefox volunteer.

Display name. день сумо trɔe

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Hello there again


https://support.mozilla.org/en-US/kb/manuals-account-configuration

http://kb.mozillazine.org/Thunderbird_:_FAQs_:_SMTP_Authentication


maybe something is not filled in correctly with an update, the necessary topics have been updated, but things can also be filled in incorrectly due to the update itself.

to try that the smtp settings will have to be checked as you sent the message. before continuing with your computer.

Try to do this with the manual I sent you.


Greetings Firefox volunteer.