Sitefinity 3.7 cmsentrypoint.aspx Request timed out.

Hi,

One of our sites is running slowly and sometimes does not load at all. When reviewing the Event Logs we get the following 

We get the following on this url  sitefinity/cmsentrypoint.aspx
Exception information: 
    Exception type: HttpException 
    Exception message: Request timed out.

Is there anyway of pinpointing the problem? 

Thanks