Where is the server log file when using grafana web?

Hi, I am trying to connect to mySql datablase, i am using grafana web version.
The datasource is not connecting and the message is “Query failed. Please inspect Grafana server log for details”. The docs explains “If you encounter an error or problem, then you can check the Grafana server log. Usually located at /var/log/grafana/grafana.log on Unix systems or in <grafana_install_dir>/data/log on other platforms and manual installations.” But where I can find the server log in the grafana web version?

Thanks in advance.

did you find where is the log file located ? Even i have the same problem