If you are using IIS as the server,then this occurs because the server takes default asp.net database.
In IIS server,create your own application pool and run your app on that instead of using the default pool.
Check the permissions.Give full access control rights.
Also,
go to SQL server configuration>properties. Select local system in the built-in app.. And your new pool should also have local system selected.
This fixed the problem for me. Hope it works for someone here.
PS: If you are trying to making connectivity in Visual studio for android application,then close the visual studio before running it on android as the process wont complete if visual studio is open and will result into error.