A Intranet is nothing but a web application which runs in the domain environment of an organization and will not accessible outside of that LAN. The best example is localhost homepage which is completely private and restricted to the domain environment unless you are making your server IP public. So you can develop any application with any technology and you need to be host it in IIS in a private network to make it Intranet.

Please explain the error message with screenshot to provide you the answer.

Are you using the Scaffholding entity framework techniques like create update delete and read operations which will actually make changes to the database??.. please apply those methods instead of db.SaveChanges(); as those are mainly integrated to perform CRUD operations on database and more over in your present code you are just reading the values from database and not updating or inserting anything and how you expect to commit changes to database bro? Think about it ok.