Emails from Yahoo being rejected (550)

[johnisotank]

Hi everyone, seemingly every email that comes from yahoo's servers are being rejected and I was hoping someone could help me figure out why.. This is an exert from one the rejected emails..

17/05/2012 14:31:23 77.238.189.59 nm2.bullet.mail.ird.yahoo.com HELO - +nm2.bullet.mail.ird.yahoo.com 250
17/05/2012 14:31:23 77.238.189.59 nm2.bullet.mail.ird.yahoo.com MAIL - +FROM:<user@btopenworld.com> 250
17/05/2012 14:31:23 77.238.189.59 nm2.bullet.mail.ird.yahoo.com RCPT - +TO:<user@mydomain.co.uk> 550
17/05/2012 14:31:23 77.238.189.59 nm2.bullet.mail.ird.yahoo.com QUIT - nm2.bullet.mail.ird.yahoo.com 240

the original user is @btopenworld.com but looks like it routes through yahoo. Every other 550 error in my log file comes from a yahoo address. Sorry I can't provide more info as this is the only place I know to look)

Thanks in advance

John

 

[Zelandakh]

The third line is a 550 failed due to relaying denied. Sounds like your server is turning down the email from yahoo because it is saying that the sender domain is btopenworld.com.

Are you doing any address validation such as SPF check, reverse proxy or similar? That will be the culprit. Sender validation is failing - I'd be able to email you as my sending email address matches my HELO and my reverse proxy and my SPF record.

Hope this helps.