Sometimes Mail Detected as spam
i have zimbra with hostname(example) : mail.zimbra.com, and make another domain inside it with name zimbra.com and used it as primary domain at global config.
so my accounts will be : email@example.com, firstname.lastname@example.org not email@example.com, firstname.lastname@example.org.
and this is my configuration :
[root@mail ~]# cat /etc/hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
192.168.0.5 mail.zimbra.com mail
dig mx to mail.zimbra.com and zimbra.com return with QUESTION, ANSWER, and AUTHORITY section. And the status was noerror
[root@ ~]# host 192.168.0.5
18.104.22.168.in-addr.arpa domain name pointer mail.zimbra.com.
the problem is, when i send mail to gmail or yahoo, it still detected mail as spam, and i still get "Warning - Reverse DNS does not match SMTP Banner" from mxtoolbox.com.
for additional information, my server run under Port Address Translation,,
any ideas ?
sorry for my bad english, and Thanks !