Message type: E = Error
Message class:  ICC_FI_CN - Für die Meldungen extern vornum. Belege 
Message number: 056
Message text: Format of reference document &1 invalid
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The SAP error message ICC_FI_CN056, which states "Format of reference document &1 invalid," typically occurs in the context of financial transactions, particularly when dealing with document references in the SAP system. This error indicates that the format of the reference document number provided does not conform to the expected format defined in the system. Causes: Incorrect Document Number Format: The reference document number may not match the expected format (e.g., length, character type).
Configuration Issues: The system may have specific settings or configurations that define valid formats for document numbers, and these may not be aligned with the input. Data Entry Errors: Manual entry of the document number may have introduced typographical errors or invalid characters. Custom Development: If there are custom programs or enhancements, they may not handle the document number correctly. Solutions: Check Document Number Format: Verify that the reference document number you are entering adheres to the expected format. This includes checking the length,
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