Message type: E = Error
Message class:  UMB_AH - Aggregation Hierarchy 
Message number: 026
Message text: First select an infuencing scorecard
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The SAP error message UMB_AH026, which states "First select an influencing scorecard," typically occurs in the context of SAP's Business Performance Management (BPM) or SAP Analytics Cloud (SAC) when users are trying to work with scorecards or performance management tools without first selecting a relevant influencing scorecard.
Cause: No Scorecard Selected: The most common cause of this error is that the user has not selected an influencing scorecard before attempting to perform an action that requires one. User Interface Navigation: The user may have navigated to a section of the application that requires a scorecard to be selected but did not do so.
Configuration Issues: There may be issues with the configuration of the scorecards or the data model that prevent the selection of a scorecard.
Solution: Select an Influencing Scorecard: Navigate to the relevant section of the application where you need to work with scorecards. Look for an option to select or choose an influencing scorecard. This
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