How To Fix /IWFND/MED_CHECK028 - Reference type for '&1' not declared

SAP Error Message - Details

• Message type: E = Error

• Message class: /IWFND/MED_CHECK -

• Message number: 028

• Message text: Reference type for '&1' not declared

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message /IWFND/MED_CHECK028 - Reference type for '&1' not declared ?

  The SAP error message /IWFND/MED_CHECK028 Reference type for '&1' not declared typically occurs in the context of SAP Gateway and OData services. This error indicates that the system is unable to find a reference type for the specified entity or property, which is represented by &1. This can happen for several reasons, including misconfigurations in the OData service, missing metadata, or issues with the data model.
  Causes:
  
  Missing Reference Type Declaration: The reference type for the entity or property is not declared in the metadata of the OData service.
  Incorrect Data Model: The data model may not be correctly defined, leading to inconsistencies in the service.
  Service Activation Issues: The OData service may not be properly activated or registered in the SAP Gateway.
  Namespace Issues: There may be issues with the namespace configuration, leading to the system not recognizing the reference type.
  Transport Issues: If the service was transported from one system to another, there may be missing components or inconsistencies.
  
  Solutions:
  
  Check Metadata: Ensure that the reference type is correctly defined in the metadata of the OData service. You can check this by accessing the service's metadata URL (e.g., /sap/opu/odata/sap/<service_name>/$metadata).
  Define Reference Type: If the reference type is missing, you may need to define it in the data model (e.g., in the ABAP Dictionary or the corresponding CDS view).
  Activate the Service: Go to the SAP Gateway Service Builder (transaction code /IWFND/MAINT_SERVICE) and ensure that the service is activated. If it is not, activate it.
  Check Namespace: Verify that the namespace is correctly configured and that the reference type is included in the correct namespace.
  Rebuild the Service: If changes were made to the data model, you may need to regenerate the service. This can be done in the Service Builder.
  Transport Consistency: If the service was transported, ensure that all necessary components are included in the transport request and that they are correctly imported into the target system.
  
  Related Information:
  
  Transaction Codes:
  
  /IWFND/MAINT_SERVICE: Service Maintenance for OData services.
  /IWFND/ERROR_LOG: To check error logs related to OData services.
  
  
  SAP Notes: Check for relevant SAP Notes that may address specific issues related to this error message.
  Documentation: Review the SAP Gateway documentation for best practices on defining and managing OData services.
  
  By following these steps, you should be able to identify and resolve the issue causing the /IWFND/MED_CHECK028 error message.