Error in Log file DSN: Service unavailable

Hello,

I am running a mail server.

Mails sent from our server do not get delievered to our client.

These mails succesfully get delievered to any other domain like gmail.com etc.

When I checked the log I found following error :

Apr 17 11:54:07 mx8 sendmail[13932]: r3H6O525013932: from=<sender@domain.com>, size=22065, class=0, nrcpts=1, msgid=<001301ce3b33$90fffef0$b2fffcd0$@com>, proto=ESMTP, daemon=MTA, relay=xx.xx.xx.xx.static-pune.hostin.in [xx.xx.xx.xx] (may be forged)
Apr 17 11:54:07 mx8 sendmail[13932]: r3H6O525013932: to=<recipient@domain.com>, delay=00:00:00, mailer=esmtp, pri=52065, stat=queued
Apr 17 11:54:24 mx8 MailScanner[13976]: r3H6O525013932: Logged to MailWatch SQL
Apr 17 11:55:29 mx8 sendmail[14069]: r3H6O525013932: to=<recipient@domain.com>, delay=00:01:22, xdelay=00:01:00, mailer=esmtp, pri=142065, relay=mx2.recipient.com. [xx.xx.xx.xx], dsn=4.0.0, stat=Deferred: Connection timed out with mx2.recipient.com.
Apr 17 12:09:33 mx8 sendmail[19712]: r3H6O525013932: to=<recipient@domain.com>, delay=00:15:26, xdelay=00:00:14, mailer=esmtp, pri=232065, relay=mx2.recipient.com. [xx.xx.xx.xx], dsn=5.0.0, stat=Service unavailable
Apr 17 12:09:33 mx8 sendmail[19712]: r3H6O525013932: r3H6dJvf019712: DSN: Service unavailable

Please help me to solve this.

Thanks
Anup

There are 3 related errors here

Apr 17 11:55:29 mx8 sendmail[14069]: r3H6O525013932: to=<recipient@domain.com>, delay=00:01:22, xdelay=00:01:00, mailer=esmtp, pri=142065, relay=mx2.recipient.com. [xx.xx.xx.xx], dsn=4.0.0, stat=Deferred: Connection timed out with mx2.recipient.com.
Apr 17 12:09:33 mx8 sendmail[19712]: r3H6O525013932: to=<recipient@domain.com>, delay=00:15:26, xdelay=00:00:14, mailer=esmtp, pri=232065, relay=mx2.recipient.com. [xx.xx.xx.xx], dsn=5.0.0, stat=Service unavailable
Apr 17 12:09:33 mx8 sendmail[19712]: r3H6O525013932: r3H6dJvf019712: DSN: Service unavailable

The first is the key
' Connection timed out with mx2.recipient.com.'.
You need to check this, maybe by talking to the Admin of that box and/or try telnet by hand to port 25 on that box; can you reach it it and does it have a listening MTA on port 25.

Incidentally, this ' relay=xx.xx.xx.xx.static-pune.hostin.in [xx.xx.xx.xx] (may be forged)' is not really good either, but may not be fatal.

Hello chrism,

Thanks for reply.

I tried telnetting to recipient domain it refused message.

telnet mx2.recipient.com 25
Trying 14.140.233.75...
Connected to mx2.recipient.com.
Escape character is '^]'.
220 EXGWSRV102.recipient.co.in Microsoft ESMTP MAIL Service, Version: 6.0.3790.4675 ready at Thu, 18 Apr 2013 09:41:27 +0530
ehlo
250-EXGWSRV102.recipient.co.in Hello [xx.xx.xx.xx]
250-TURN
250-SIZE
250-ETRN
250-PIPELINING
250-DSN
250-ENHANCEDSTATUSCODES
250-8bitmime
250-BINARYMIME
250-CHUNKING
250-VRFY
250-X-EXPS GSSAPI NTLM LOGIN
250-X-EXPS=LOGIN
250-AUTH GSSAPI NTLM LOGIN
250-AUTH=LOGIN
250-X-LINK2STATE
250-XEXCH50
250 OK
mail from:sender@domain.com
250 2.1.0 sender@domain.com....Sender OK
rcpt to:recipient@domain.com
250 2.1.5 recipient@domain.com
data
354 Start mail input; end with <CRLF>.<CRLF>
subject:test email
test
.
550 5.7.1 Requested action not taken: message refused
Connection closed by foreign host.

This "relay=xx.xx.xx.xx.static-pune.hostin.in [xx.xx.xx.xx]" is our
shared hosting email server there are lot of client on it not having any problem
while sending/receiving emails.

Any Idea?

You need to talk to the admin of that server mx2.recipient.com. He can watch the logs while you try to do that.
He should know anyway; looks like your local system is not an acceptable system for them.

Re other problem; you should try to get to the bottom of that also. It may(?) not seem to be causing a problem right now, but in the long run it may come back to bite you.