I get from different mail servers: There was a SMTP communication problem with the recipient's email server. Please contact your system administrator. < #5.5.0 smtp;550 Relaying is prohibited> When I check the log file, it says 2002-07-15 12:05:14 mail1.transplatinum.com OutboundConnectionCommand SMTPSVC1 FLEETONE_MAIL - 25 RCPT - TO:<xxxxx@xxxxxxxxx> 0 0 4 0 17375 SMTP - - - - 2002-07-15 12:05:14 mail1.transplatinum.com OutboundConnectionResponse SMTPSVC1 FLEETONE_MAIL - 25 - - 550+Relaying+is+prohibited 0 0 26 0 17484 SMTP - - - - 2002-07-15 12:05:14 mail1.transplatinum.com OutboundConnectionCommand SMTPSVC1 FLEETONE_MAIL - 25 RSET - - 0 0 4 0 17484 SMTP - - - - 2002-07-15 12:05:14 mail1.transplatinum.com OutboundConnectionResponse SMTPSVC1 FLEETONE_MAIL - 25 - - 250+OK+-+Reset 0 0 14 0 17656 SMTP - - - - Is this being caused on my end or their end? It happens not with every email address, but quite a few we send out to.