Message type: E = Error
Message class:  PPC1DM - PP Backflush: Database Management and Communication 
Message number: 301
Message text: Internal error: incorrect combination IF_HIERARCH and IF_MODE
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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The SAP error message PPC1DM301, which states "Internal error: incorrect combination IF_HIERARCH and IF_MODE," typically indicates an issue related to the configuration or usage of the planning functions in SAP, particularly in the context of SAP Integrated Business Planning (IBP) or SAP Advanced Planning and Optimization (APO).
Cause: Incorrect Configuration: The error may arise from an incorrect configuration of the planning hierarchy or mode settings in the planning function. This could be due to mismatched settings in the planning area or the planning function itself. Data Inconsistency: There may be inconsistencies in the data being processed, such as missing or incorrect entries in the master data or planning data. Version Issues: Sometimes, the error can be related to version compatibility issues, especially if there have been recent updates or changes in the system. Custom Code: If there are custom enhancements or modifications in the planning functions, they might not be handling the hierarchy and mode
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