Have you tried checking the settings? Probably there is the problem and at the same time the solution

Zimbra is a popular email and collaboration suite, and its statistics service helps monitor and track various metrics related to email usage and system performance.

Check Service Status: Begin by checking the current status of the Zimbra statistics service. You can do this by logging into the Zimbra Admin Console and navigating to the "Server Status" section or using command-line tools like zmcontrol.

Thank you. This worked for me.

Thank you for the answer.

Just do the below steps to overcome this issue.......

  # chown zimbra:zimbra /opt/zimbra/zmstat/
  # su zimbra
  $ zmstatctl status   
  $ /cd /opt/zimbra/zmstat/pid/
  $ rm zmstat-fd-real.pid
  $ zmstatctl start
  $ zmstatctl status

Thank you ...........! above steps is helps me lot and now zimbra mail server is work fine.