Message type: E = Error
Message class:  SD_FREE_GOODS_MSG - Message class for Free Goods maintenance 
Message number: 021
Message text: Distribution channel is required.
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The SAP error message SD_FREE_GOODS_MSG021 indicates that a distribution channel is required for processing free goods in the Sales and Distribution (SD) module. This error typically occurs when you are trying to create or process a sales order, delivery, or billing document that involves free goods, but the system cannot find a valid distribution channel associated with the transaction.
Cause: Missing Distribution Channel: The distribution channel field is not filled in the sales order or the relevant document.
Configuration Issues: The distribution channel may not be properly configured in the system for the relevant sales area (Sales Organization, Distribution Channel, Division). Master Data Issues: The customer master or material master may not have the necessary data for the specified distribution channel.
Solution: To resolve the error, you can take the following steps: Check Sales Order/Document: Ensure that the distribution channel is filled in the sales order or document you are trying to process. You can do this by
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