Re: [Sonic #6410040] keep getting bounces when sending to a particular domain

[http://dummy.us.eu.org/robert (Robert )]

I looked carefully at the DNS domain records.  They all look fine.  The
only one weirdness is that the MX record's hostname has a leading
underscore in the hostname.  I'm thinking that that's what tripping up
Sonic.NET's SMTP server.  It may be looking for the first alphabetic
character, skipping over the underscore, and then trying to do the
hostname lookup from there, and it fails.

I am unlikely to be able to convince the domain name owner to change the
hostname for the MX record since it's working through
inmotionhosting.com's infrastructure.

For the time being, using a port 25 connection to unumhumbrewing's SMTP
server for messages directed there works OK.

Please feel free to close this ticket.

 > From: http://www.sontec.sontrak.net/~support
 > Date: Sat, 29 May 2021 16:35:56 -0700
 >
 > Hi there,
 > 
 > We didn't get a bounce-back message after sending the email, but we found an 
 > error message in our logs when we sent an email to that domain. We suspect that 
 > there is an issue with the mx records that might be causing mail to bounce or 
 > get rejected.
 > 
 > Best regards, 
 > 
 > Chris H
 > Technical Support Representative 1
 > 
 > http://www.sonic.net/~support Sonic.
 > Sonic. Support 2260 Apollo Way
 > 1.855.394.0100 (Tech Support) Santa Rosa, CA 95407
 > 1.707.547.2199 (FAX) http://sonic.com/support