I am trying to process a Direct Retro using a chartstring I believe to be valid, however, I receive an error message when I try to submit. What should I do?

I am trying to process a Direct Retro using a chartstring I believe to be valid, however, I receive an error message when I try to submit: 'Combination Code Validation Failed with Reason: Failure: Invalid Combination.... Please correct the respective chart field value/s and retry. If error persists contact system administrator' What should I do?

Please use the chart of accounts validation lookup to verify your chartstring. 

For C&G managed funds, you will need to enter PC Business Unit, PC Project, PC Activity, and correct Chartfield 1 and Chartfield 2 fields (if they are mapped out).