Hi akshay,
Do you mean nothing at all ? the web.log file is totally empty ?
Or the web.log file is not mentioned/service not started?
or the web.log file exists, but it appears empty because you selected an old date and the log rotation has switched to the web_2.log file ? Then after a size limit it is over, the old lines are erased.
So please confirm the date selected from/to, check if you didn't type a char in the filter at the top right of the page, etc.
Or use direct access server to check log files.
Regards
J-Serge