Problem
You may receive this error if you have not specified a general ledger account for the payment type in ServiceTitan.
Solution
Edit payment type
In ServiceTitan:
Click the Settings icon.
In the side panel, click Invoicing > Payment and Invoice Types.

Click Edit for that payment type and add the account associated with the payment.

On the Accounting Page, pull up the Batch with the error > Right Click + Reload anywhere on the screen to hard refresh the page > export the Batch.