Email delivery failure

I have encountered an email recipient that is rejected. This is the first time I have contacted this person. I have not had this problem with any other sent emails. I am able to receive their email but even when I reply to their post I get a delivery failure from postmaster@icop.cc. Is this something on my end or theirs?

This is a partial message regarding the failure.

Action: failed
Status: 5.7.1 (Permanent failure - security: delivery not authorised, message refused)
Remote-MTA: dns; mail.cyberback.com
Diagnostic-Code: smtp; 550 5.7.1 Client host rejected


Any help on correcting this problem would be appreciated.



Thanks,
TRoof

 

http://www.eudora.com/techsupport/kb/1593hq.html

I would say that one of several possibilities exist.
One is that you are trying to reply to spam and the address listed is spoofed, it is not real, or it has restricted access.
The second would be that this ISP has blocked email comming from your ISP because someone at your ISP is spamming them (or more specifically their customers) and when contacted, your ISP choose to take no action.
Third would be similar, except that your ISP had been blackholed as a spam server to one or the databases they use.
Fourth would be that there is an error on the dns server your ISP is using and they are not sending it correctly.

 

Thanks for the reply Pete.

No's 1 and 4 are not the likely culprits. Not sure about 2 and 3.

Received this email from the person I am trying to email. "I just checked with my provider. I explained the problem, he did a little manipulating and said to try again. "

I just tried sending again with the same results. I guess a little manipulating didn't work.

I will let it be known if this problem is resolved some how just to bring this thread to a proper end.

Thanks,

TRoof