Signinmanager passwordsigninasync problem with entity framework

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C#

MVC4

entity-framework

hi Friend
im beginner in MVC
im use entity framework code first for my database , and MVC (ASP.NET Identity)
before it, i add tables of user identity of mvc4 to my database , now when i want to login or register i get this error
A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 50 - Local Database Runtime error occurred. Cannot create an automatic instance. See the Windows Application event log for error details.
)
please help me to handle it
sorry for my poo english

What I have tried:

i try to use linq for this but did not work