One of my users is having issues, everytime he send an email he gets this error. Is it my server or what? From: Delivery Subsystem [mailtoOSTMASTER@xxxxx.com] Sent: Thursday, December 01, 2005 7:30 AM To: firstname.lastname@example.org Subject: Message Delivery Delay Message is waiting at server01 for delivery to mail.xxxxx.com. Message delivery has been delayed to the following recipients: [SMTP:email@example.com]: Remote SMTP Server Returned: 451 4.7.1 Temporarily rejected. Try again later.