Message type: E = Error
Message class:  APPL_MM_PUR_SOS_SL - Messages for Source List 
Message number: 009
Message text: Enter a valid value for the blocked source of supply indicator.
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The SAP error message APPL_MM_PUR_SOS_SL009 indicates that there is an issue with the "blocked source of supply" indicator in the system. This error typically arises when a user attempts to perform an action related to a source of supply (like a vendor or a purchasing info record) that has not been properly configured or does not have a valid value assigned to the blocked source of supply indicator.
Cause: Invalid Value: The blocked source of supply indicator is set to a value that is not recognized by the system.
Configuration Issues: The configuration settings for the source of supply may not be correctly set up in the system. Data Entry Error: There may have been a mistake in data entry when setting up the source of supply or during the transaction. Missing Master Data: The relevant master data (like vendor or material master) may not be properly maintained.
Solution: Check the Indicator Value: Ensure that the value
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