SAP S/4HANA Error 5420: Content Filter Unknown Error

Access the SAP Fiori Launchpad and navigate to the 'Manage Content Filters' app (or equivalent transaction/app for your specific S/4HANA version and installed components).

Locate the content filter that is causing the error 5420. This might involve searching by filter name, ID, or the affected application/OData service.

Review the configuration of the identified content filter. Pay close attention to the filter conditions, applied entities, and any custom logic or ABAP code involved.

Check for any syntax errors, incorrect references to fields or entities, or invalid filter expressions. If custom logic is used, ensure it's syntactically correct and compatible with the current S/4HANA version.

If issues are found, correct them and save the changes. If no obvious issues are found, try deactivating and then reactivating the content filter. This can sometimes reset internal states and resolve transient errors.

Test the application or functionality that was previously encountering the error to confirm it's resolved.

Identify the OData service being used by the application or functionality that triggers the error 5420. This information can often be found in the browser's developer tools (Network tab) or by consulting application documentation.

Access the SAP Gateway Client (transaction /IWFND/GW_CLIENT) or the SAP Fiori Apps Reference Library to inspect the OData service definition.

Verify that the OData service is active, correctly registered, and has no errors reported in transaction /IWFND/ERROR_LOG.

Examine the metadata of the OData service (e.g., by appending '$metadata' to the service URL in the Gateway Client). Ensure that the properties and entities referenced in the content filter's configuration actually exist and are correctly defined in the service.

If the content filter involves custom logic (e.g., ABAP code), analyze the corresponding Data Manipulation Language (DML) statements or business logic within the OData service implementation. Ensure that data retrieval and manipulation are sound and don't lead to unexpected results that the filter cannot handle.

If necessary, consider re-generating or re-activating the OData service. If the issue is related to data model inconsistencies, this might require adjustments in the underlying ABAP CDS views or other data sources.

Access the SAP Solution Manager or SAP NetWeaver Administrator (NWA) for your S/4HANA system.

Navigate to the system logs (e.g., SM21 for ABAP system logs or Log Viewer in NWA for Java/cross-component logs).

Filter the logs for entries around the time the error 5420 occurred. Look for any related error messages, warnings, or dumps that might provide more context about the 'Content Filter Unknown Error'.

If available, enable and review traces for the affected OData service or application. This can include Gateway traces (transaction /IWFND/TRACES) or application-specific traces.

Analyze the trace output to pinpoint the exact operation or data access that is failing and is not being correctly handled by the content filter. Look for specific SQL errors, ABAP dumps, or exceptions.

Based on the detailed information from the logs and traces, you can then take more targeted corrective actions, such as adjusting the content filter configuration, fixing issues in the OData service, or addressing underlying data inconsistencies.