Error message when sending to a group

Hello,

Everytime I use a specific group to send an e-mail, one of the receipient give me this error:

03/03/2009 14:08:25 Router: Error transferring message 00684761 via SMTP to smtp.GUEVREMONT.NET;smtp1.GUEVREMONT.NET,smtp2.GUEVREMONT.NET OF7077F8FA:B25C8FE6 ON8525756E:00684761 551 5.7.1 Receive of data is denied

And if I send the same e-mail only to this receipient, it is working. What is the logic behind this?

To me, sending to a group or to only one person is the same thing.

Any idea?

Thanks

Subject: error message when sending to a group

it’s not the same to the recipient’s mail server. they may see an e-mail addressed to many people as a SPAM attempt and are rejecting it.