but I could not find any mention of it in the manuals, and believe me I looked.

 

I have a subscriber who all of a sudden has been generating some error reports that I see, and the message is as follows (with the subscriber's address changed to protect the innocent):

 

There was a SMTP communication problem with the recipient's email server. Please contact your system administrator.

  <mail.dlhost.com #5.5.0 smtp;550 RCPT TO:[log in to unmask]> Relaying not allowed <mailto:[log in to unmask]> Relaying not allowed>  

 

I looked for everything I could find, but first went at it looking for some sort of error based on relaying and couldn't find anything about it.  Tried looking for other bits and pieces and did not get any hits, either.  

 

If anyone can point me in the right direction I would appreciate it.  My provider made some security changes not long ago and things were pretty much hosed for some time, but I finally got him back on track.  I would like to know if this error is caused by something on the subscriber's end or if it is due to my provider.  

 

Next I am going to see if I can figure out why some addresses generate errors sporadically, which is very hard to track ...

 

Thanks in advance.