550 administrative prohibition

Hi All,

on my Symanteg Getway, i see that there are several outbound email that are failed for a specific user.

I the details, i see "550 administrative prohibition"

What does it means this error ?

IMHO I guess that the problem is on the destination server (and that error is reported from that server) since the sender is rejecting this email (i guest due to the fact that the sender is empty).

I'm right ???

Thanks in advance.