[cobalt-users] Mail format error: 501 5.6.0 Data Format Error

["Will Nordmeyer" <will@xxxxxxxxxxx>]

I keep getting the following error when I send mail from my RAQ3 with
RAQ4 OS (other domains on this server work, this one domain, which is
the primary domain, does not): 

----- The following addresses had permanent fatal errors -----
<recv@xxxxxxxxxxxx>
(reason: 553 <domusera@xxxxxxxxxx>... No such user here)
----- Transcript of session follows -----
... while talking to mail.receiver.net.:
>> MAIL From:<domusera@xxxxxxxxxx> SIZE=3485
<<< 553 <domusera@xxxxxxxxxx>... No such user here
501 5.6.0 <recv@xxxxxxxxxxxx>... Data format error

If I use the alias (usera) instead of domusera, the same error occurs,
just with usera instead of domusera. 

my DNS records:
domain.com -> A -> IP
mail.domain.com -> A -> IP
ns1.domain.com -> A -> IP
ns2.domain.com -> A -> IP2
www.domain.com -> A -> IP
domain.com mail is sent to high priority mail server mail.domain.com
 
in the RAQ control panel for the site (it's the primary site on the
server),
host is ns1
domain is domain.com
web aliases are domain.com www.domain.com
e-mail aliases are domain.com, mail.domain.com, www.domain.com

usernames are:
domusera, with alias usera
domuserb, with alias userb
virtusertable has the entries:
domusera@xxxxxxxxxxxxxx domusera
domuserb@xxxxxxxxxxxxxx domuserb
usera@xxxxxxxxxxxxxx domusera
userb@xxxxxxxxxxxxxx domuserb

#accept at domains:
@mail.domain.com %1@xxxxxxxxxxxxxx
@www.domain.com %1@xxxxxxxxxxxxxx
@domain.com %1@xxxxxxxxxxxxxx

There... I think I covered everything. 

Thanks for a hopefully quick response! 

--Will