Web Applicaton Not Found

You are developing in Visual Studio and your code access your local SharePoint server. On running the application, you get the following error:

 

 

Figure 1: The web application at XXX could not be found.

Error is as following:

The web application at http://server could not be found. Verify that you have typed the URL correctly. If the URL should be serving existing content, the system administrator may need to add a new request URL mapping to the intended application.

If you are developing in Visual Studio 2010 and the program compiles without issues the only thing you should check is the “Platform target” option in Project settings. SharePoint 2010 is a 64-bit application. You should select x64 in the platform target. By default, x86 (32-bit) is selected. Your program will compile but you will not be able to access the SharePoint web application. Change it to x64 and it should work.