HTTP Error 404.17 : The requested content appears to be script and will not be served by the static file handler

You may got error while browsing your ASP.NET website, which reads  "HTTP Error 404.17 : The requested content appears to be script and will not be served by the static file handler "

Please see below error snap

Probable causes:

 There are many causes behind this problem
1.  HTTP Handler configured to handle the request has certain preconditions set, but its Application pool does not meet some or all of these preconditions, in simple words Application pool's .NET framework is not set properly to the application in which it is compiled (If my application developed in 4.5 and I am attaching application pool with framework 2.0)

2. If my application is migrated from IIS 6 then My Application pool should running in Classic Mode, with enable 32 bit mode options

3. Required .NET framework has restriction in 'ISAPI and CGI restrictions' in IIS

Solutions :

Problem can be resolved by following steps
1. Open IIS manager (Go to start - Run - type 'INETMGR')
2. Select the Server Name (System Name)
3. Select ISAPI and CGI restrictions in right side pane
4. Allow the Not Allowed restrictions for required framework
5. If your required framework will not exist in ISAPI and CGI restrictions  then you need to re-registered framework with following command
see below snippet, to know how to allow ISAPI and CGI restrictions 

6. Go to Start - Run put following command in Run window

C:\Windows\Microsoft.NET\Framework\v4.0.30319 \aspnet_regiis -I

see below snippet

Here I have given example for .NET Framework 4.0 you can use same command for any .NET framework.

7. Set required .NET version in application pool
8. Enable '32-Bit Applications' in application pool
9. Restart IIS

That all, Now try to browse the same website, we have resolved the bug.