A server I'm taking care of uses qmail for MTA. I can send and receive to almost every domain except one or two that give the following error, or something very similar:

550-Verification failed for <[email protected]>
550-No Such User Here
550 Sender verify failed

From what I understand from this article the remote host tries to send an email to my host to see if the mailbox really exists.

I tried the same commands with telnet from my laptop, and i get 250 ok answers, leading to think that the user does indeed exist.

Why then does the remote host not get the same response I did?

How can I check if traffic from the remote host is indeed routable to my sending host?

Any other sugggestions?


  • I have had to deal with this in the past and what we did was contact the receiving email server admin, who had to change his settings. Can you contact them?
    – charnley
    Apr 6, 2011 at 0:53
  • Try telnetting not from your laptop but from the mail server itself.
    – DmitryK
    Apr 6, 2011 at 2:26
  • From the destination host to the sending host you mean? I would love to do that, but unfortunately I do not have access to the destination host, only the sender.
    – jfoucher
    Apr 6, 2011 at 8:19

3 Answers 3


This is not your fault. This is a fault of your recipient's server.

Doing "sender verify" is always a bad idea. You have to convince the recipient to stop this behavior as this is not a suitable antispam method.

But anything you do to fix it on your side is a waste of time.

  • 3
    All those stupid arguments in "WHY it is a bad idea" are not compelling absolutely. If you send mail with lame FROM:, it's bad idea and it's your problem. And yeah, it's your fault
    – poige
    Apr 24, 2013 at 4:50
  • Though your answers is useful in clarifying the problem, it is no solution as one never know which sever will reject the next post
    – user209249
    Feb 13, 2014 at 15:12
  • It's not a solution because it's not your problem... You can't rely on servers to respond to VRFY verbs, and if you do then it's your own problem; not the people that you wont be able to communicate with. RFC2520 (1999) Section 2.11 states that VRFY should be disabled.
    – Chris S
    Feb 13, 2014 at 19:59

This is most likely because you are using a From field which differs from the actual mailbox account name.

Some SMTP servers are configured to reject such an inconsistency.

So, for example, if your real account name is [email protected], you cannot send emails as [email protected].

  • This was exactly my problem. Changed the "from address" and email started working right away. I'm using cPanel for SMTP. Jun 6, 2018 at 14:33

I had same error. It worked after I added root:[email protected]:mail.example.com line to /etc/ssmtp/revaliases file.

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