Over the last few days Mail.app started refusing to send my emails from any of my email accounts. I use only one smtp server for all the accounts: smtp.att.yahoo.com, on port 25 with non SSL authentication.
The solution that worked for me was to simply replace the "att" in the mail server name with "mail". It seems that some of the machines that are used behind the dns name smtp.att.yahoo.com started having this problem, but not all: the server smtp.mail.yahoo.com is still OK.
Thanks to Steve McGarrett for this solution.
Thanks -- that would explain why I had to hit "send" 4 or 5 times before it worked. So far now it's working every time.
Posted by: JJ on May 3, 2008 2:57 AMi am reciving following error:
The server rejected the sender address. The server response was: 530 5.7.0 Must issue a STARTTLS command first. a4sm731935tib.4
Posted by: jignesh kadvani on November 28, 2008 6:28 AMsame problem comes to me.
Posted by: anil on May 20, 2009 3:14 AMThe message could not be sent because the server rejected the sender's e-mail address. The sender's e-mail address was 'babymatch2009@gmail.com'. Subject 'Re: Moto match - spec', Account: 'pop.gmail.com', Server: 'smtp.gmail.com', Protocol: SMTP, Server Response: '530 5.7.0 Must issue a STARTTLS command first. c20sm12867748rvf.40', Port: 25, Secure(SSL): No, Server Error: 530, Error Number: 0x800CCC78
Posted by: Anonymous on May 23, 2009 3:38 AM