So all of a sudden, after a week of using it, I get an error message on my zabbix server
gui (http://localhost/zabbix/.)
The error says: Zabbix serve
As Zabbix Senior Instructor and Consultant Hernandes Martins says in his "Zabbix server is not running what to do?" blog post:
This is the first step that should be checked regardless of the situation, always view the logs, from the moment the error message appeared in the zabbix web interface always view the log.
By following his advice I could be able to identify the cause of the issue with my Zabbix server, and then apply the solution related to the specific problem.
In my case, as I've commented in the page:
The problem in my server was of "4. Resource Allocation Issues". Just like you wrote above, Zabbix was showing out of memory errors on the log when trying to start the server.
After increasing the value of parameter CacheSize I tried to restart the service, but it didn't respond. So, I ended up restarting the whole machine. Fortunately, in the end it resolved the problem for good.
So, take a look at the log with command tail -f /var/log/zabbix/zabbix_server.log
on the terminal/prompt, watch for any errors, and tackle the problem according to what it makes sense for your particular case.