After registration of “Rebelleon” LLC I had problems signing up for an online
account at the Tax Service. For some reason the phone number required during
the sign-up process was rejected despite the fact that I entered it exactly as
found in the certificate of the LLC. I described the issue in an email message
to online_support@taxserivce.am sent from my rebelleon.am email address. The
latter is a (not so) tricky combination of free services by
Gmail, Forward Email and
SendGrid. Sending from that address is performed via
SendGrid, while receiving message to that address works via Forward Email and
Gmail. There was no reponse to my inquiry for more than a day so I decided to
check the stats in my SendGrid account and found out that the said message was
blocked by mx1.taxservice.am due to what turned out to be a Sender Address
Verification failure (the
exact error reported by the mail server was 550 5.7.1 Sender ID (PRA) Not Permitted). The linked Wikipedia article lists a number of limitations of that
procedure and my setup obviously belongs to one of those cases. I resubmitted
my support request from my gmail address. It’s good to know that emails sent
from my rebelleon.am address may be rejected by some paranoid mail servers. I
will decide what to do about it later.