Yahoo Error Code 550 Mail Box Unavailable

[shank]

I have 3 Yahoo email accounts in POP Peeper, one has been returning the subject error for more than 1 week when sending mail, will still receive mail. I am able to send mail from the subject account using the Android app, Windows webmail interface. Pop Peeper is able to respond to mail received by the subject address by selecting another Yahoo address.

I would be most grateful for any help resolving this issue.

--- Version ---
OS: Windows 7 (x64)
POP Peeper: 4.5.2.0
Webmail: 4.5.10.0
SSL: 1.0.2.11
IMAP: 4.5.2.0
SendMail: 4.5.2.0
AntiJunk: 4.0.1.0 (disabled)
Spell Checker: 4.0.1.0 (disabled)
Web of Trust: 4.0.1.0 (disabled)

--- Error ---
XXXXXXX [1000: IMAP] ['imap.mail.yahoo.com' (993) SSL: 1] [Smtp: 'smtp.mail.yahoo.com' (587) SSL: 2] [consec: 1]
- Send Mail: Error verifying message terminator
Server Returned: Request failed; Mailbox unavailable (#550)

2.0.0 OK (#250)

[Jeff]

It may mean that there's a recipient in your outgoing mail that doesn't exist. Or, it may mean you're trying to send FROM an account that Yahoo doesn't recognize.

You can view the problematic message by viewing the "Outbox" tab above the message list. From there, you can either edit it to fix the problem or delete it. If you still want to send it or want to know what the problem is and you don't see a problem, contact me via email (support at esumsoft dot com) and we'll take a look at it.

[shank]

Thank you for the reply.

I attempted to forward an example message to the support email, same error was returned.

All settings, configuration appears identical to that of the functioning account, suspect account sent mail properly until recently.

[mjs]

Hi shank,

Try forwarding the message to Jeff as an attachment:

forward as attachment.png (18.54 KiB) Viewed 3685 times

In the message window click on menu option "Message">"Forward as attachment..." and send the attached message to Jeff.

[Jeff]

It's not necessary to forward the attachment, you just need to contact me via email so that I can see what the problem is via logging.

[shank]

That appears to have worked!

[shank]

It is also possible to send a message out from the suspect account that was received from a different account.

[Jeff]

It's possible that the format of the original message you were trying to send looked suspicious to Yahoo and they were blocking it as potential spam. By changing it to "forward as attachment", it may have looked less spammy.