interesting case for "SQL Server does not exist or access denied." error

My connection string is :

server=localhost;Database=INFOSEC;Integrated Security=true

It works for the login page, but it does not work for the registration page, and give the "SQL Server does not exist or access denied." error.

Any IDEA?

You shouls check your connection string properly and make sure you are calling proper database for registration form.Otherwise can you give the code here.So i can findout the error.