I am Matsumoto, the mail administrator.
I work for a Japanese company.
I can’t mail to “messagelabs.com”. I would like you to investigate.
cluster4.us.messagelabs.com[18.104.22.168]:25, delay=3628, delays=3625/0.02/2/0.36, dsn=2.0.0, status=sent
2.Service Temporarily Unavailable.
cluster4a.us.messagelabs.com[22.214.171.124]:25, delay=72, delays=0.02/0/69/2.8, dsn=4.0.0, status=deferred (host cluster4a.us.messagelabs.com[126.96.36.199] said: 421 Service Temporarily Unavailable …
From cluster4 to cluster4a?
There was no problem at this site.
I think that it is probably blocked.
Or, the evaluation of IP may be dropped.