QuickBooks Online Sync Error | A business validation error has occurred while processing your request | Business Validation Error: Select a customer for each billable split line.

The error "Select a customer for each billable split line" occurs in QuickBooks Online when billable tracking is on and a billable line is missing its Customer/Job mapping. To clear it, make sure Billable tracking is set up correctly in QBO and that any billable expense account has an income account assigned.

Please try these steps in QuickBooks Online:

1. Check your billable settings: Gear icon > Company Settings > Expenses > Bills and expenses. Confirm "Track billable expenses and items as income" is configured as desired.
2. If you use "multiple accounts," edit each expense account used for billable lines: Gear icon > Chart of Accounts > select the expense account > Edit > enable "Use for billable expenses" and choose an Income Account > Save.
3. In Ramp: Ensure the Customer/Job field is enabled and populate a Customer on each billable split of the transaction.
4. Reattempt the sync: Go to Accounting > Ready to sync and retry.

These steps address the QuickBooks validation that is blocking the sync.