The Fund used in the invoice distribution is required to balance by a characteristic that is currently out of balance. 

Open General Ledger to verify the Fund requirements in order to resolve:

1. In General Ledger, go to Configuration> Funds
2. Double click on the fund to open the Fund record to confirm the distribution requirements
3. Note the characteristics that have a check mark in the Required to Balance column
4. Go back to the invoice in Accounts Payable
5. Update the existing distribution in order to balance by all applicable characteristics
6. Save the invoice