The Web application at could not 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.

Error:

The Web application at could not 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.

Solution:

change the visual studio solution to 64 bit in properties as per the below screenshot.

Thats it...