ASP.Net Error 26 Error Locating Server/Instance Specified

Question

I can't figure out what I'm doing wrong here. I've tried everything: my connection string, turned off firewall, allowed remote connections, but I still keep getting this error:

A network-related or instance-specific error occurred while establishing a connection to the 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: 26 - Error Locating Server/Instance Specified)

[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: 26 - Error Locating Server/Instance Specified)] System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection, Action 1 wrapCloseInAction) +6568558 System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose) +717 System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity, Boolean withFailover) +6595000 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) +6597311 System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(TimeoutTimer timeout, SqlConnectionString connectionOptions, SqlCredential credential, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance) +6597891 System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions, SessionData reconnectSessionData) +942 System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions) +1162 System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool pool, DbConnection owningObject, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOptions userOptions) +72 System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection) +6601145 System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection) +103 System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection) +2102 System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource 1 wrapCloseInAction) +6568558 System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose) +717 System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity, Boolean withFailover) +6595000 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) +6597311 System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(TimeoutTimer timeout, SqlConnectionString connectionOptions, SqlCredential credential, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance) +6597891 System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions, SessionData reconnectSessionData) +942 System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions) +1162 System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool pool, DbConnection owningObject, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOptions userOptions) +72 System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection) +6601145 System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection) +103 System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection) +2102 System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource 1 wrapCloseInAction) +6568558 System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose) +717 System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity, Boolean withFailover) +6595000 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) +6597311 System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(TimeoutTimer timeout, SqlConnectionString connectionOptions, SqlCredential credential, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance) +6597891 System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions, SessionData reconnectSessionData) +942 System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions) +1162 System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool pool, DbConnection owningObject, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOptions userOptions) +72 System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection) +6601145 System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection) +103 System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection) +2102 System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource 1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection) +116 System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, Tas kCompletionSource 1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal& connection) +1079 System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource 1 retry, DbConnectionOptions userOptions) +6605639 System.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource 1 retry) +233 System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource 1 retry) +278 System.Data.SqlClient.SqlConnection.Open() +239 System.Data.Entity.Infrastructure.Interception.InternalDispatcher 1.Dispatch(TTarget target, Action 2 operation, TInterceptionContext interceptionContext, Action 3 executing, Action 3 executed) +207 System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.Open(DbConnection connection, DbInterceptionContext interceptionContext) +438 System.Data.Entity.SqlServer.<>c__DisplayClass33.b__32() +582 System.Data.Entity.SqlServer.<> c__DisplayClass1.b__0() +15 System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute(Func 1 operation) +263 System.Data.Entity.SqlServer.SqlProviderServices.UsingMasterConnection(DbConnection sqlConnection, Action 1 act) +749 System.Data.Entity.SqlServer.SqlProviderServices.DbCreateDatabase(DbConnection connection, Nullable 1 commandTimeout, StoreItemCollection storeItemCollection) +314 System.Data.Entity.Migrations.Utilities.DatabaseCreator.Create(DbConnection connection) +329 System.Data.Entity.Migrations.DbMigrator.EnsureDatabaseExists(Action mustSucceedToKeepDatabase) +230 System.Data.Entity.Internal.DatabaseCreator.CreateDatabase(InternalContext internalContext, Func 3 createMigrator, ObjectContext objectContext) +130 System.Data.Entity.Database.Create(DatabaseExistenceState existenceState) +267 System.Data.Entity.CreateDatabaseIfNotExists 1.InitializeDatabase(TContext context) +217 System.Data.Entity.Internal.InternalContext.PerformInitializationAction(Action action) +66 System.Data.Entity.Internal.InternalContext.PerformDatabaseInitialization() +596 System.Data.Entity.Internal.RetryAction 1.InitializeDatabase(TContext context) +217 System.Data.Entity.Internal.InternalContext.PerformInitializationAction(Action action) +66 System.Data.Entity.Internal.InternalContext.PerformDatabaseInitialization() +596 System.Data.Entity.Internal.RetryAction 1.PerformAction(TInput input) +208 System.Data.Entity.Internal.LazyInternalContext.InitializeDatabaseAction(Action 1 action) +263 System.Data.Entity.Internal.InternalContext.GetEntitySetAndBaseTypeForType(Type entityType) +39 System.Data.Entity.Internal.Linq.InternalSet 1.Initialize() +72 System.Data.Entity.Internal.Linq.InternalSet 1.get_InternalContext() +21 System.Data.Entity.Infrastructure.DbQuery 1.System.Linq.IQueryable.get_Provider() +64 System.Data.Entity.QueryableExtensions.FirstOrDefaultAsync(IQueryable 1 source, Expression 1 predicate, CancellationToken cancellationToken) +218 System.Data.Entity.QueryableExtensions.FirstOrDefaultAsync(IQueryable 1 source, Expression 1 predicate) +113 Microsoft.AspNet.Identity.d__13.MoveNext() +229 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +144 System.Runtime.CompilerServices.TaskAwaiter.Hand leNonSuccessAndDebuggerNotification(Task task) +84 Microsoft.AspNet.Identity.d__d.MoveNext() +455 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +144 System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +84 System.Runtime.CompilerServices.TaskAwaiter 1.GetResult() +49 Microsoft.AspNet.Identity.AsyncHelper.RunSync(Func 1 func) +235 DaveyMaherFitness.Logic.RoleActions.AddUserAndRole() +151

[HttpException (0x80004005): 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: 26 - Error Locating Server/Instance Specified)] System.Web.HttpApplicationFactory.EnsureAppStartCalledForIntegratedMode(HttpContext context, HttpApplication app) +12601933 System.Web.HttpApplication.RegisterEventSubscriptionsWithIIS(IntPtr appContext, HttpContext context, MethodInfo[] handlers) +175 System.Web.HttpApplication.InitSpecial(HttpApplicationState state, MethodInfo[] handlers, IntPtr appContext, HttpContext context) +304 System.Web.HttpApplicationFactory.GetSpecialApplicationInstance(IntPtr appContext, HttpContext context) +404 System.Web.Hosting.PipelineRuntime.InitializeApplication(IntPtr appContext) +475

[HttpException (0x80004005): 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: 26 - Error Locating Server/Instance Specified)] System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +12618980 System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +159 System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +12458597

Any advice would be appreciated, I feel like I'm just overlooking something!

Answer 1

That simply states it could not establish a connection to the server and there could be dozen reason for that .

It could be the SQL-SERVER configured Windows Mode Authentication and you are trying sql-server authentication . Or your sql-server is not configured for the remote connection or you are using wrong credential . or worst your connection string is not correct.

Any way , I highly recommend use Server panel in VS , and make test connection on that panel , It's much easier for you to figure it out what's wrong .