Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints

Few days ago i found an error in RDLC report after published. The client claims that sometimes the report shows fine but sometimes shows the error. Then i test this report in my development PC but no luck. I can not generate any error. After that in my testing i found an error like below:"An error has occurred during report processing.Exception has been thrown by the target of an