This error message suggests that the zabbix_server process is already running and cannot be started again because the PID file (/tmp/zabbix_server.pid) is locked. The error code [11] indicates that the resource (PID file) is temporarily unavailable, which typically occurs when another process has already locked the file.
To resolve this issue, you should check whether the zabbix_server process is actually running by using the ps command or checking the logs. If the process is running, then try to stop it first before starting it again. If you are sure that no other process is using the PID file, then you can manually delete the lock file and start the process again.
To delete the PID file, run the following command:
sudo rm /tmp/zabbix_server.pid
Then, start the zabbix_server process again using the appropriate command for your system.
