Hi,
All of the sudden, we can't send any email to one particular domain, and
below is the error message we got. Does anyone have any idea how to fix
this problem? Thanks!
Charles
------------------------------------------------------------
This is the mail system at host es1.mydomain.com.
I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.
For further assistance, please send mail to postmaster.
If you do so, please include this problem report. You can
delete your own text from the attached returned message.
The mail system
<myn...@mail.xxdomain.com>: connect to
xxdomain.com[2607:f220:404:8104::80e7:5a78]:25: Network is
unreachable
