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Cannot send e-mail from Thunderbird

Andy Schiltz
Andy Schiltz
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When I try to send e-mails from Thunderbird through my Yahoo mail account, I get the following error message: "An error occurred while sending mail. The mail server responded: Request failed; Mailbox unavailable. Please check the message and try again."

I have updated the POP and SMTP passwords, deleted them from Thunderbird and re-entered them with no solution.

I can receive e-mails from my Yahoo account, just cannot send. I can send and receive e-mails from my Yahoo web account using Firefox or Chrome.

SMTP account settings: Description: Yahoo! Mail Server name: smtp.mail.yahoo.com Port: 465 User Name: the same one I use to log into Yahoo! Mail web Authentication Method: Normal password Connection Security: SSL/TLS

Thanks, Andy

When I try to send e-mails from Thunderbird through my Yahoo mail account, I get the following error message: "An error occurred while sending mail. The mail server responded: Request failed; Mailbox unavailable. Please check the message and try again." I have updated the POP and SMTP passwords, deleted them from Thunderbird and re-entered them with no solution. I can receive e-mails from my Yahoo account, just cannot send. I can send and receive e-mails from my Yahoo web account using Firefox or Chrome. SMTP account settings: Description: Yahoo! Mail Server name: smtp.mail.yahoo.com Port: 465 User Name: the same one I use to log into Yahoo! Mail web Authentication Method: Normal password Connection Security: SSL/TLS Thanks, Andy

Chosen solution

Are you using a different reply-to address then you are sending with? I have the same problem as you when my reply is set to my domain name email address that is unable to send messages. If I change the reply-to adress to be the same @sbcglobal.net address as I use to actually send, it will work and not give the "mailbox unavailable" error....

Read this answer in context 👍 4

All Replies (6)

christ1
christ1
  • Top 25 Contributor
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Authentication Method: Normal password

Change that to 'OAuth2'.

Andy Schiltz
Andy Schiltz Question owner
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Unfortunately, problem not solved.

Changed Authentication Method to OAuth2 and tried to send an e-mail. Yahoo requested my log-in and password, which were accepted, but I still received the same "Mailbox unavailable" error message when it Thunderbird tried to send the e-mail.

Restarted Thunderbird a couple of times, no change. Rebooted computer once, no change.

christ1
christ1
  • Top 25 Contributor
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Did you make the change for the outgoing server?

You may also need to allow cookies for https://login.yahoo.com in Thunderbird.

Andy Schiltz
Andy Schiltz Question owner
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I made the change for the SMTP server, not for the POP server as OAuth2 is not a menu option for the POP server settings. See attached screen shots.

The yahoo.com domain is whitelisted in Thunderbird cookies, at Tools/Options/Privacy/Web Content/Show Cookies... . See the attached screen shots.

Thanks.

absolute.eng
absolute.eng
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Chosen Solution

Are you using a different reply-to address then you are sending with? I have the same problem as you when my reply is set to my domain name email address that is unable to send messages. If I change the reply-to adress to be the same @sbcglobal.net address as I use to actually send, it will work and not give the "mailbox unavailable" error....

Andy Schiltz
Andy Schiltz Question owner
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Yep, that did it! Thank you very much!

Is this a recent change to Yahoo? Having them different worked for me up until about a week ago.