Problem with (Service Check Timed Out)

Hello All.
I have a problem with one of my switches.
I have the critical state with the problem Service Check Timed Out.

I have search but I do not with the folder /etc/nagio to change the file nagios.cfg and put more time in order to solve the issue.
I have the 2.0.0p20 (CRE) version, I do not know if the nagios.cfg file is in other folder or where exactly is.

Can you give me any idea of how to fix the problem??

You need to edit service_check_timeout in $OMD_ROOT/etc/nagios/nagios.d/tuning.cfg

Thank you very much for the answer!!!

I change the parametrer into 90 and the problem is solved.