Troubleshooting Zimbra Service Disruption and SSL Error

Recently, one of our clients encountered an issue while accessing Zimbra services. Suddenly, all functionalities within the system displayed an “❌” symbol, rendering email sending and receiving unavailable.

Upon SSH access to the Zimbra mail server, it was confirmed that the server was running normally, and the Zimbra SSL certificates were still valid. An attempt to restart the service using the “zmcontrol restart” command resulted in an error message: “Unable to start TLS: SSL connect attempt failed error:1416F086” on the Zimbra mail server. After searching the Zimbra forum, I found a solution to address this issue and would like to share it in case others encounter a similar situation.

To resolve this problem, I disabled the SSLv3 protocol and restarted the service. Here are the steps you can follow:

First, SSH into the Zimbra mail server and switch to the zimbra user using the command:

su - zimbra

Next, run the following two commands:

zmlocalconfig -e ldap_starttls_required=false
zmlocalconfig -e ldap_starttls_supported=0

After executing these two commands, stop, start, and restart the Zimbra services with the following commands:

zmcontrol stop
zmcontrol start
zmcontrol restart

And here is the result after I performed these steps. Wishing you successful resolution if you encounter a similar situation.