LinuxQuestions.org - T=remote_smtp defer (-53): retry time not reached for any host

Hello,
I just configured debian 8 mailserver with ispmanager 5.
I am using exim4 and dovecot for receiving and sending emails and have a little troubles with delivering emails.
I have endian firewall with opened and redirected ports to private network where mailserver is.
if I try telnet IP 25, I have a respond:

Code:

Connected to mail2.computersoft.cz.

Escape character is '^]'.

220 mailserver.computersoft.cz ESMTP Exim 4.84_2 Thu, 17 Mar 2016 08:57:43 +0100

but when I try to send email to some mailbox, no email is received and I get this log:

Code:

2016-03-17 08:38:18 1agSVe-00078k-7O DKIM: d=gmail.com s=20120113 c=relaxed/relaxed a=rsa-sha256 [verification succeeded]

2016-03-17 08:38:18 1agSVe-00078k-7O From ondrassssek@gmail.com to test@computersoft.sk X-Spam_score: -49983.

2016-03-17 08:38:18 1agSVe-00078k-7O <= ondrassssek@gmail.com H=mail-ob0-f171.google.com [209.85.214.171] P=esmtps X=TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128 S=12215 id=CADH7t7V=RQRW9wY1sxo2ZKgq8CHmtYr8eJ3jWHB_av6zvxi8Qg@mail.gmail.com from <ondrassssek@gmail.com> for test@computersoft.sk

2016-03-17 08:39:53 1agRxR-0006kn-QH mail2.computersoft.cz [81.2.234.61] Connection timed out

2016-03-17 08:39:53 1agRxR-0006kn-QH == test@computersoft.sk R=dnslookup T=remote_smtp defer (110): Connection timed out

2016-03-17 08:39:53 1agRsd-0006dp-Ou == test@computersoft.sk R=dnslookup T=remote_smtp defer (-53): retry time not reached for any host

2016-03-17 08:39:53 1agRzw-0006m4-FM == test@computersoft.sk R=dnslookup T=remote_smtp defer (-53): retry time not reached for any host

2016-03-17 08:39:53 1agRuc-0006jD-3q == test@computersoft.sk R=dnslookup T=remote_smtp defer (-53): retry time not reached for any host

2016-03-17 08:39:54 1agSAC-0006vH-R3 == test@computersoft.sk R=dnslookup T=remote_smtp defer (-53): retry time not reached for any host

2016-03-17 08:39:54 1agRmK-0006aW-6h == test@computersoft.sk R=dnslookup T=remote_smtp defer (-53): retry time not reached for any host

2016-03-17 08:39:54 End queue run: pid=27429

2016-03-17 08:40:26 1agSVe-00078k-7O mail2.computersoft.cz [81.2.234.61] Connection timed out

2016-03-17 08:40:26 1agSVe-00078k-7O == test@computersoft.sk R=dnslookup T=remote_smtp defer (110): Connection timed out

2016-03-17 08:59:35 SMTP syntax error in "\377\364\377\375\006\377\364\377\375\006\377\364\377\375\006\377\364\377\375\006\377\364\377\375\006" H=129.234.forpsi.net [81.2.234.129] unrecognized command

2016-03-17 08:59:36 SMTP syntax error in "" H=129.234.forpsi.net [81.2.234.129] unrecognized command

2016-03-17 08:59:36 SMTP syntax error in "" H=129.234.forpsi.net [81.2.234.129] unrecognized command

2016-03-17 08:59:36 SMTP syntax error in "ds" H=129.234.forpsi.net [81.2.234.129] unrecognized command

2016-03-17 08:59:36 SMTP call from 129.234.forpsi.net [81.2.234.129] dropped: too many unrecognized commands (last was "ds")

2016-03-17 09:01:17 1agSrt-0007IR-Mh DKIM: d=seznam.cz s=beta c=relaxed/relaxed a=rsa-sha256 t=1458201678 [verification succeeded]

2016-03-17 09:01:18 1agSrt-0007IR-Mh From DevilDark@seznam.cz to test@computersoft.sk X-Spam_score: -49992.

2016-03-17 09:01:18 1agSrt-0007IR-Mh <= DevilDark@seznam.cz H=mxh2.seznam.cz [77.75.76.26] P=esmtps X=TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256 S=2730 id=huI.Ss25.5O7xQ9g3YpE.1MwcHB@seznam.cz from <DevilDark@seznam.cz> for test@computersoft.sk

2016-03-17 09:03:25 1agSrt-0007IR-Mh mail2.computersoft.cz [81.2.234.61] Connection timed out

2016-03-17 09:03:25 1agSrt-0007IR-Mh == test@computersoft.sk R=dnslookup T=remote_smtp defer (110): Connection timed out

2016-03-17 09:04:48 Warning: purging the environment.

 Suggested action: use keep_environment.

2016-03-17 09:04:49 Warning: purging the environment.

 Suggested action: use keep_environment.

2016-03-17 09:04:49 Warning: purging the environment.

 Suggested action: use keep_environment.

2016-03-17 09:04:49 exim 4.84_2 daemon started: pid=28424, -q30m, listening for SMTP on port 25 (IPv6 and IPv4) port 587 (IPv6 and IPv4) and for SMTPS on port 465 (IPv6 and IPv4)

2016-03-17 09:04:49 Start queue run: pid=28425

2016-03-17 09:04:49 1agRxR-0006kn-QH == test@computersoft.sk R=dnslookup T=remote_smtp defer (-53): retry time not reached for any host

2016-03-17 09:04:49 1agRsd-0006dp-Ou == test@computersoft.sk R=dnslookup T=remote_smtp defer (-53): retry time not reached for any host

2016-03-17 09:04:49 1agSAC-0006vH-R3 == test@computersoft.sk R=dnslookup T=remote_smtp defer (-53): retry time not reached for any host

2016-03-17 09:04:49 1agRzw-0006m4-FM == test@computersoft.sk R=dnslookup T=remote_smtp defer (-53): retry time not reached for any host

2016-03-17 09:04:49 1agRuc-0006jD-3q == test@computersoft.sk R=dnslookup T=remote_smtp defer (-53): retry time not reached for any host

2016-03-17 09:04:49 1agSrt-0007IR-Mh == test@computersoft.sk R=dnslookup T=remote_smtp defer (-53): retry time not reached for any host

2016-03-17 09:04:49 1agSVe-00078k-7O == test@computersoft.sk R=dnslookup T=remote_smtp defer (-53): retry time not reached for any host

2016-03-17 09:04:49 1agRmK-0006aW-6h == test@computersoft.sk R=dnslookup T=remote_smtp defer (-53): retry time not reached for any host

2016-03-17 09:04:49 End queue run: pid=28425

2016-03-17 09:05:01 1agSvV-0007Ol-Aq DKIM: d=gmail.com s=20120113 c=relaxed/relaxed a=rsa-sha256 [verification succeeded]

2016-03-17 09:05:01 1agSvV-0007Ol-Aq From ondrassssek@gmail.com to test@computersoft.sk X-Spam_score: -49983.

2016-03-17 09:05:01 1agSvV-0007Ol-Aq <= ondrassssek@gmail.com H=mail-oi0-f53.google.com [209.85.218.53] P=esmtps X=TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128 S=13061 id=CADH7t7WTjsO6X4u5B-oi6r-Gf-SihM7rES_cmnOv9CQ=NZdRPw@mail.gmail.com from <ondrassssek@gmail.com> for test@computersoft.sk

2016-03-17 09:05:02 1agSvV-0007Ol-Aq == test@computersoft.sk R=dnslookup T=remote_smtp defer (-53): retry time not reached for any host

I really dont know what is wrong. DNS are set up corectly and its working great with the same DNS config on old server.

thank you for help