Hi harikk81,
there is the web log inside your OMD Site: /omd/sites/[SITE_ID]/var/log/web.log.
You can increase the loglevel to see more/detailed information.
Please go to global settings and search for Logging in the ‘USER INTERFACE’ Category.
There is also an apache directory inside your OMD Site: OMD[Site]:~/var/log/apache$
Here you can find some information about the request to the intance apache.
BR
Anastasios