I have a server with two SQL Server instances on it.
I can connect to both of them remotely from any ware in the world however I can't connect to one of them in my local network.
I can't find any problem I can connect to both of them out side my network but one of them is not working in my local network.
I can connect to both instance from out side my network using my public IP address so there is no problem with my firewall and ports. If I'm out side my network i can login to both instance with "sa" user, but when I'm in my local network i can only connect to one of them and the other is not working.
Microsoft.Data.SqlClient.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) at Microsoft.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose) at Microsoft.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, SqlConnectionString connectionOptions, Boolean withFailover) at Microsoft.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, Boolean ignoreSniOpenTimeout, TimeoutTimer timeout, Boolean withFailover) at Microsoft.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString connectionOptions, SqlCredential credential, TimeoutTimer timeout) at Microsoft.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(TimeoutTimer timeout, SqlConnectionString connectionOptions, SqlCredential credential, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance) at Microsoft.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions, SessionData reconnectSessionData, Boolean applyTransientFaultHandling, String accessToken, DbConnectionPool pool) at Microsoft.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions) at Microsoft.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool pool, DbConnection owningObject, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOptions userOptions) at Microsoft.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection) at Microsoft.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection) at Microsoft.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection) at Microsoft.Data.ProviderBase.DbConnectionPool.WaitForPendingOpen() --- End of stack trace from previous location --- at Microsoft.Data.SqlClient.SqlRetryLogicProvider.ExecuteAsync(Object sender, Func1 function, CancellationToken cancellationToken) at Microsoft.Data.SqlClient.SqlRetryLogicProvider.ExecuteAsync(Object sender, Func1 function, CancellationToken cancellationToken) at Microsoft.SqlTools.ServiceLayer.Connection.ReliableConnection.ReliableSqlConnection.<>c_DisplayClass30_0.<b0>d.MoveNext() in
What I have tried:
1- Set Port from manger TCP/IP
2- Restart the server
3- Disable the Firewall