Why the sync error occurs
This error occurs when a payment can't sync to Xero because the payment amount is greater than the open balance of the bill or invoice in Xero. The amount of a payment must be less than or equal to the open balance on the bill or invoice to sync successfully to Xero.
How to fix the sync error
Remove any duplicate manually applied payment from the bill or invoice in Xero and sync again.
If the error doesn't clear or the payment does not need to sync, contact Customer Support for additional assistance.