A network-related or instance-specific error occurred while establishing a conne

[SqlException (0x80131904): 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.
)]
   System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction) +6670530
   System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose) +688
   System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity, Boolean withFailover) +6696948
   System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, Boolean ignoreSniOpenTimeout, TimeoutTimer timeout, Boolean withFailover) +219
   System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString connectionOptions, SqlCredential credential, TimeoutTimer timeout) +6699136
   System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(TimeoutTimer timeout, SqlConnectionString connectionOptions, SqlCredential credential, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance) +6699595
   System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions) +610
   System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions) +1049
   System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool pool, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOptions userOptions) +74
   System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnectionOptions userOptions) +6702163
   System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnectionOptions userOptions) +78
   System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection) +2192
   System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection) +116
   System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection) +1012
   System.Data.ProviderBase.DbConnectionClosed.TryOpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions) +6706787
   System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry) +152
   System.Data.SqlClient.SqlConnection.Open() +229
   System.Data.SqlClient.SqlProviderServices.UsingConnection(SqlConnection sqlConnection, Action`1 act) +134
   System.Data.SqlClient.SqlProviderServices.UsingMasterConnection(SqlConnection sqlConnection, Action`1 act) +3800051
   System.Data.SqlClient.SqlProviderServices.GetDbProviderManifestToken(DbConnection connection) +10949674
   System.Data.Common.DbProviderServices.GetProviderManifestToken(DbConnection connection) +91

[ProviderIncompatibleException: The provider did not return a ProviderManifestToken string.]
   System.Data.Common.DbProviderServices.GetProviderManifestToken(DbConnection connection) +10949745
   System.Web.Providers.ModelHelper.CreateMetadataWorkspace(String providerName, DbConnection connection, String csdl, String ssdl, String msl) +168
   System.Web.Providers.ModelHelper.CreateEntityConnection(ConnectionStringSettings setting, String csdl, String ssdl, String msl) +298
   System.Web.Providers.ModelHelper.CreateMembershipEntities(ConnectionStringSettings setting) +51
   System.Web.Providers.DefaultMembershipProvider.Membership_CreateUser(String applicationName, String userName, String password, String salt, String email, String passwordQuestion, String passwordAnswer, Boolean isApproved, DateTime& createDate, Boolean uniqueEmail, Int32 passwordFormat, Object& providerUserKey) +306
   System.Web.Providers.DefaultMembershipProvider.CreateUser(String username, String password, String email, String passwordQuestion, String passwordAnswer, Boolean isApproved, Object providerUserKey, MembershipCreateStatus& status) +1252
   System.Web.UI.WebControls.CreateUserWizard.AttemptCreateUser() +409
   System.Web.UI.WebControls.CreateUserWizard.OnNextButtonClick(WizardNavigationEventArgs e) +221
   System.Web.UI.WebControls.Wizard.OnBubbleEvent(Object source, EventArgs e) +584
   System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args) +84
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3804