Increase request timeout in IIS

Add this to your Web Config

<system.web>
    <httpRuntime executionTimeout="180" />
</system.web>

This time-out applies only if the debug attribute in the compilation element is False. Therefore, if the debug attribute is True, you do not have to set this attribute to a large value in order to avoid application shutdown while you are debugging. 
The default is 110 seconds.

Refer this page:
 https://msdn.microsoft.com/en-us/library/e1f13641(v=vs.100).aspx for full references of httpRuntime