Service '?' Unknown

If a "service '?' unknown" error message is shown when attempting to connect to a Message Server, the cause could be related to a custom configuration value in the SAP Logon Pad or SAPLOGON.INI file.  When the SAP Logon Pad connects to a Message Server it uses a value in the SAPLOGON.INI file under the [MSSrvPort] section which specifies which port it should connect on.  If this value has been changed manually then ERP² will not connect correctly.  This is because the default behaviour of the SAP .NET connector is to attempt to connect on a port name based on the System ID.


  • An entry has been configured in the SAP Logon Pad with the System ID of PRD
  • The SAPLOGON.INI entry for the system has the [MSSrvPort] item has been changed to sapms00
  • The SAP Logon Pad will connect on port sapms00
  • The SAP .NET Connector will attempt to connect on port sapmsPRD

The above scenario will fail if no service entry has been created for sapmsPRD.  To resolve this an entry must be configured in the SERVICES file usually contained in \WINDOWS\SYSTEM32\DRIVERS\ETC.  An example of a service entry is shown below:

sapmsPRD  3600/tcp

The port number (3600 in the above example) can be determined from one of your SAP technical staff or by looking for the port name specified in the SAPLOGON.INI file.  Using the above example, if the SAPLOGON.INI [MSSrvPort] entry pointed to sapms00 then you would need to search in the SERVICES file for the entry sapms00.  The port number will appear to the right of the entry and you can copy this value to the new sapmsPRD entry.

To determine which line in the SAPLOGON.INI file relates to the system causing the error, follow these steps:

  • Open SAPLOGON.INI in notepad (Usually contained in \Windows)
  • Search for the display name of the system (This is what is displayed in the SAP Logon Pad)
  • The result should be something like:  Item4=SAP Production
  • When you look under the [MSSrvPort] section you will need to look for the line that begins Item4=