A co-worker (whose home PC has been seriously infected with assorted trojans and viruses) started getting this message when sending emails to certain email addresses. I Googled it, but didn’t get much info other than it might be trojan/virus related.
What’s the dope?
Try Googling SMTP 550. SMTP is the Simple Mail Transfer Protocol
Here’s the first result.
Here is the RFC for SMTP.
Wow - that was helpful, Quartz - first you link him to the wrong error message (he’s getting “permit denied” errors, not “unable to relay” errors) and then you link him to the RFC, which is always easy for newbies to read), and then you give him an example of “user unknown” - which is also NOT his problem!
The problem is that SMTP error 550 is somewhat generic, meaning only that the “requested action was not taken”. This can happen for any number of reasons. In this particular case, I can’t say for sure what the problem is without seeing the headers from the returned email, but “permit denied” indicates that the user’s IP or user account has been blacklisted by either the outbound email server or the recipient’s POP server. If he can send some emails, then the latter would seem to be the problem. Again, without additional data, a definitive answer is not possible at this time.
It might serve your friend better to call his ISP’s tech support line, as this “cuts out a middleman”, so to speak.
And to tag on to this - if I had to guess, I’d say that when your friends machine was jacked by the virii and/or spyware/worm/etc., his/her email addy was hijacked and used to send out spam or other annoying email. This would cause some POP server admins to institute the abovementioned blacklisting on your co-worker in order to avoid any more spam coming from him/her. Again - just a guess…
It’d be a cast iron b!tch to clean up, but the first step should be (as mentioned above) for your co-worker to contact their customer service.
Hope this helps,
David