Field Integrity Exception

Hello,



I am trying to fix an error in a rule, but I am unsure how to fix this error without just excluding these account ID's so that it will run successfully. Any ideas?



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Rule Error:



[FIELD_INTEGRITY_EXCEPTION : Upsert/Update is unable to honor the uniqueness criteria of the target object OR unable to map to right field type. Example: Such error occurs when Opportunity id field is mapped to Account id filed.]