>Is it normal for mail servers to continually try to deliver to an account >after it receives a 450 message
yes, 4xx means "transient reject, try to send the message later" 5xx means "fatal reject, don't try to deliver the message again" >Failed to deliver to domain domain.com after 54 tries. >Last error was: >I/O error encountered > > > >How can I avoid this? Fix your i/o error, unless "i/o error" is one of your policies! :)) Len
