[BlueOnyx:25895] Re: sendmail issue with fairly new 5210R server

[Michael Stauber]

Hi Larry,

>   Have a fairly new 5210R server that for some reason
> is giving a "User unknown" error on sendmail connections
> for existing, in use accounts.  Cannot find any link between
> when a message fails and others go through fine.
> 
>    Sendmail is giving a reject 550 5.1.1 <user at domain> User unknown
> on connects, but then will connect and accept the next message
> to the same user.
> 
>    Any ideas where to look ?

This could a number of things, so it's hard to say without taking a look.

Is there *any* user on the Vsite in question that is able to receive email?

If no: Then this is possibly an email server alias issue. In that case 
look here: https://www.blueonyx.it/dns-for-email

It could also be that in the Vsite settings under "Services" / "Email" 
you have "Disable Email for Domain" ticked.

If it works for some users on a Vsite, but not for others? In that case 
either the user is using an email alias that is forbidden, or in the 
settings of that User under "Basic Settings" you have "Disable User's 
Email" ticked.

I would step back and start at the most basic level to check.

Say the Vsite is named "www.company.com" and has the Email Server Alias 
"company.com". The username is "site1_joe" and he has the Email Alias "joe".

Attempts to mail to joe at company.com fail? Try emailing to the account 
name and the FQDN of the Vsite: site1_joe at www.company.com and see if 
that also fails.

If that also fails, then it may not just be an Email Server Alias and 
User Alias issue, but something more fundamental. Then it is (again) 
time to step back to this guide: https://www.blueonyx.it/dns-for-email

That's to make really sure the DNS and Aliases are correctly configured. 
Because that's the most common point of failure.

Also: Make sure not to enter the FQDN of the Vsite into "Email Server 
Alias" field as well. So if the Vsite is called "www.company.com", then 
you do NOT put that as well into the "Email Server Alias" field. Instead 
it gets just "company.com" and possibly (but not necessarily) 
"mail.company.com".

Let me know how it goes. If you need any additional help? File a Support 
Ticket via the GUI and tick the checkbox "Allow Access" and I'll take a 
look.

-- 
With best regards

Michael Stauber