[BlueOnyx:25898] Re: sendmail issue with fairly new 5210R server

[Larry Smith]

Michael,

All users are receiving mail.
disable email is not checked for site or users.

Hmmm, if I remove the FQDN of the site from
email aliases, it removes it from the local-host-names
file (in /etc/mail/) and all mail starts to fail.
Two other domains on the box do not react this way
and their FQDN is not in email aliases but IS in the
local-host-names file.

Everything will work fine for hours, then suddenly 
a single user on this domain will get the "User unknown"
error and that message is bounced, then it will
likely work fine for hours again or may fail several
times.

 Have read through the dns-for-email several times 
and believe everything is setup correctly.

 Stumped at this point.

-- 
Larry Smith
lesmith at ecsis.net

On Thu January 5 2023 15:58, Michael Stauber wrote:
> 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.