Hi, I developed an application which has being used more than 100 users. Currently we found two computers that have a problem for this application. This application accesses an Access mdb file on a remote server through ADO.net. The following is a piece of the codes ---------------------------------------------------------------------------------------- string theConnectionString = "Provider=MS Remote;Remote Provider=Microsoft.Jet.OLEDB.4.0;Data Source=D:\\Inetpub\\test.mdb;Remote Server=https://test.com"; connection.ConnectionString = theConnectionString; System.Data.OleDb.OleDbCommand command = new System.Data.OleDb.OleDbCommand(); command.Connection = connection; if (connection.State.ToString() == "Open") { Console.WriteLine("Connection Opened"); } else { Console.WriteLine("Connection Failed"); } command.CommandText = "SELECT * FROM dumy"; System.Data.OleDb.OleDbDataReader dataReader; dataReader = command.ExecuteReader(CommandBehavior.CloseConnection); --------------------------------------------------------------------------------------- The following is the output from the above codes: ------------------------------------------------------------------------------------------- Connection Opened System.Data.OleDb.OleDbException: Internet Client Error: Cannot Connect to Server. at System.Data.OleDb.OleDbCommand.ExecuteCommandTextForSingleResult(tagDBPARA MS dbParams, Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteCommandTextForSingleRow(tagDBPARAMS dbParams, Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteCommandText(Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteCommand(CommandBehavior behavior, Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteReaderInternal(CommandBehavior behavior, String method) at System.Data.OleDb.OleDbCommand.ExecuteReader(CommandBehavior behavior) at ConsoleApplication1.Program.Main(String[] args) in C:\Documents and Settin gs\someone\My Documents\Visual Studio 2005\Projects\ConsoleApplication1\C onsoleApplication1\Program.cs:line 35 --------------------------------------------------------------------------------------------- One of the computers has the following configuration: ---------------------------------------------------------------------------------------------- Window XP Professional Version 5.1 (Build 2600.xpsp_sp2_gdr.050301-1519 : Service Pack 2) MADC 2.8 Sp1 ON WINDOWS XP SP2 (Validated by Component Check 2.0) ---------------------------------------------------------------------------------------------- Devlelopment environments ---------------------------------------------------------------------------------------------- VB 6 VS 2003 VS 2005 I tried all three development environment and all of them have the same problem ---------------------------------------------------------------------------------------------- FACT: We know the codes are good because it works on other computers. I turned off the FireWall on the computer and there is no affect. There is no error message in the event veiwer. QUESTIONS: How to debug this kind of problem All I have is the above error message. Thanks in advance altoids