How To Fix GW491 - Parameter value is invalid

SAP Error Message - Details

• Message type: E = Error

• Message class: GW - Message Texts for Gateway

• Message number: 491

• Message text: Parameter value is invalid

Self-Explanatory Message

Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of messages in the SAP system have a message text, however this is frequently insufficient to comprehend or resolve the problem.

To make things easier, more detailed information is frequently added to describe the issue, how to fix it, and the necessary steps or configuration modifications.

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Smart SAP Assistant

• What is the cause and solution for SAP error message GW491 - Parameter value is invalid ?

  The SAP error message GW491, which states "Parameter value is invalid," typically occurs in the context of Gateway services, particularly when dealing with OData services in SAP. This error indicates that one or more parameters being passed to a service or function module are not valid or do not meet the expected criteria.
  Causes of GW491 Error
  
  
  Invalid Parameter Values: The parameters being sent in the request may not conform to the expected data types, formats, or value ranges defined in the OData service.
  
  
  Missing Required Parameters: If a required parameter is missing from the request, the service may not be able to process it correctly.
  
  
  Incorrect Data Types: Sending a string where a number is expected, or vice versa, can trigger this error.
  
  
  Service Definition Issues: There may be issues with the service definition itself, such as incorrect mappings or configurations.
  
  
  Authorization Issues: Sometimes, the error can be related to authorization problems where the user does not have the necessary permissions to access certain parameters.
  
  
  Solutions to GW491 Error
  
  
  Check Parameter Values: Review the parameters being sent in the request. Ensure that they are valid, correctly formatted, and within the expected ranges.
  
  
  Review OData Service Documentation: Consult the documentation for the OData service to understand the expected parameters and their formats.
  
  
  Use Correct Data Types: Ensure that the data types of the parameters match what the service expects. For example, if a parameter expects an integer, make sure you are not sending a string.
  
  
  Test with Minimal Parameters: If possible, try to call the service with the minimum required parameters to see if the error persists. This can help isolate the problematic parameter.
  
  
  Check Service Implementation: If you have access to the backend, review the implementation of the OData service to ensure that it is correctly handling the parameters.
  
  
  Debugging: If you have access to the SAP system, you can use transaction codes like /IWFND/ERROR_LOG to check for detailed error logs related to the OData service.
  
  
  Authorization Check: Ensure that the user making the request has the necessary authorizations to access the service and its parameters.
  
  
  Consult SAP Notes: Check the SAP Support Portal for any relevant notes or updates related to the GW491 error, as there may be known issues or patches available.
  
  
  Related Information
  
  OData Services: Understanding how OData services work in SAP can help in troubleshooting issues related to parameter handling.
  SAP Gateway: Familiarity with SAP Gateway concepts and configurations can provide insights into how services are defined and consumed.
  Transaction Codes: Familiarize yourself with relevant transaction codes such as /IWFND/MAINT_SERVICE for managing OData services and /IWFND/GW_CLIENT for testing OData services.
  
  By following these steps, you should be able to identify and resolve the GW491 error in your SAP environment.