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Old 27th November 2006, 08:38
safoo safoo is offline
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Default 550-The recipient cannot be verified email problem

Seems to be a simple problem, but I can not figure this one out:

I have a Ubuntu server setup using the perfect setup for 6.06 and with Ispconfig. This server's hostname is is on the main IP of the system. On a 2nd IP, I have Both of these sites are setup through Ispconfig. I can send and receive emails to both domains successfully from:
- from email address of one domain to the other domain
- from php scripts on the server using the php mail() function
- from my gmail account

The problem I have occurs when sending email from a different server housed at a different datacenter. The hostname is and the domain being used for sending the email is

When sending email from to, the emails go through just fine.

When sending email from to, I get the following errors:

If sending from thunderbird, it says
An error occurred while sending mail. The mail server responded: "The recipient cannot be verified. Please check all recipients of this message to verify they are valid." Please verify that your email address is correct in your Mail preferences and try again.
If sending mail from telnet 25, it accepts RCPT TO: <>, but RCPT TO:<> returns
550-"The recipient cannot be verified. Please check all recipients of this
550 message to verify they are valid."
If sending from the php mail() function using a php script on server, emails sent to go through. Any emails sent to do not come through and bounce back after few hours:
A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed:
Unrouteable address
So basically, it seems the site setup on the main IP of the server can receive emails without any problems. The problem I am having here seems to occur on a domain that is setup on a secondary IP in Ispconfig.

Thanks in advance for any help.

Last edited by safoo; 27th November 2006 at 22:10.
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