Maybe it is some kind of anti-Spam messure. Maybe they reject bulk email or there was something in the content of your mail, which triggered this. ASSP e.g. can be configured to reply 5xx to Spam Messages, so the sender will think the adress is invalid. But normal content may pass. (If this is a good practice is another question)
So the adress could be correct, but they refuse your content. Matti RD> On Wednesday, May 14, 2008, 11:20:13, Todd Richards wrote: >> ... >> Do servers ever return a 5xx, such as "unknown user" even if the user >> is there, say to combat spammers? RD> That would be a rather stupid thing to do since as Matti mentioned a 5xx RD> response means its a permanent error, don't retry. >> Or if I get an "unknown user", is it a pretty safe bet they really are >> "unknown"? RD> Quite safe. -- Matti Haack - Hit Haack IT Service Gmbh Poltlbauer Weg 4, D-94036 Passau +49 851 50477-22 Fax: +49 851 50477-29 http://www.haack-it.de To Unsubscribe: http://www.ipswitch.com/support/mailing-lists.html List Archive: http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ Knowledge Base/FAQ: http://www.ipswitch.com/support/IMail/
