Please help me. I Installed Zimbra 8.5 mail server on Centos 6.5. But unable to autheticate SMTP through outlook client from outside networks. Works well within same network. Also works well using webmail. DNS server is on Windows Server 2008 within same network.
1st check the port access form the server using telnet utility.
hi, this issue I faced, I resolved this issue from local side in outlook only.
Sol: Outgoing Mail server (SMTP) Port: 587
SMTP Authentication Required
Secure Authentication or SPA needs to be turned off
Please check once.