Zimbra 8.6-mail not sending to other domains

[phoenix]

My Zimbra 8.6 was working fine for the last 10 months. But from yesterday I noticed that the mail server is not sending email to other domain.
The error log was

Sep 19 10:48:30 pop postfix/error[18960]: 3B8C515E19A0: to=<cxxxx@gmailm>, relay=none, delay=0.17, delays=0.13/0/0/0.04, dsn=4.4.1, status=deferred livery temporarily suspended: connect to alt4.gmail-smtp-in.l.google.com[173..219.26]:25: Connection timed out)
I tried to telnet the gmail server
telnet mail.google.com 25
Trying 172.217.26.197...
Please give me some clue where to check.
Iam using the following version
Release 8.6.0_GA_1153.RHEL6_64_20141215151155 RHEL6_64 FOSS edition.

The text in red should give you a clue, this has nothing to do with your ZCS installation.

[ask2me0077]

My Zimbra 8.6 was working fine for the last 10 months. But from yesterday I noticed that the mail server is not sending email to other domain.
The error log was

Sep 19 10:48:30 pop postfix/error[18960]: 3B8C515E19A0: to=<cxxxx@gmailm>, relay=none, delay=0.17, delays=0.13/0/0/0.04, dsn=4.4.1, status=deferred livery temporarily suspended: connect to alt4.gmail-smtp-in.l.google.com[173..219.26]:25: Connection timed out)
I tried to telnet the gmail server
telnet mail.google.com 25
Trying 172.217.26.197...
Please give me some clue where to check.
Iam using the following version
Release 8.6.0_GA_1153.RHEL6_64_20141215151155 RHEL6_64 FOSS edition.

[phoenix]

Sorry to say. Iam not a professional. After checking the details I think that the problem is related to port 25. How can I check the issue.

As I said, this is nothing to do with your ZCS installation. Yes, of course it's related to "port 25" as that's how mail servers talk to each other but the problem is not likely to be with ZCS.

The information you've posted show a 'timeout' trying to connect to a gmail server, there's one or two possibilities with the information you've given. First, assuming you've copied & pasted the error correctly there is an invalid IP address shown for the server to which you're trying to connect. If you do have the correct IP address in that error message in your log file then you should use that to do a telnet connection test no the name of the server, google has many servers and you're not testing the server that's giving the problem unless you use an IP address.

The other possibility is that you have some sort of network (or firewall) problem on your server, have you checked that? You also haven't mentioned whether this problem relates to other mail servers or just google.

[ask2me0077]

Sorry to say. Iam not a professional. After checking the details I think that the problem is related to port 25. How can I check the issue.