Message type: E = Error
Message class:  CNV_DMC_SIN - Messages for s-innovations migration 
Message number: 371
Message text: Accounting Document Number is empty. Required for external numbering.
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The SAP error message CNV_DMC_SIN371 indicates that the accounting document number is empty, which is required for external numbering during a data migration or conversion process. This error typically occurs in the context of the SAP Data Migration Cockpit or during the execution of a data migration project.
Cause: Missing Document Number: The primary cause of this error is that the accounting document number is not being populated in the relevant fields during the data migration process.
Configuration Issues: There may be issues with the configuration of the external numbering system or the mapping of fields in the migration template. Data Source Issues: The source data may not contain the necessary accounting document numbers, or there may be issues with the extraction process. Incorrect Mapping: The mapping of fields in the migration template may not be correctly set up to pull the accounting document number from the source data.
Solution: Check Source Data: Ensure that the source
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