Error:

HTTP Error 500.19-Internal Server Error
The requested page cannot be accessed because the related configuration data for the page is invalid.

Solution:

Step 1: 

Start Visual studio command prompt as an administrator as shown in the picture below:

Step 2: 

In the visual studio command prompt type the command aspnet_regiis –i and then press Enter as shown in picture below:

Step 3: 

Installation process will take some time and once finished it will display finished installing message. After installation again refresh site in IIS and browse it again.