Hi there, @designfiles. I want to help you get through this so you can proceed to users purchase orders from your product to your QuickBooks Online (QBO) account.

Before we proceed with the resolution, May I ask where you received the error prompt? Was it in QuickBooks? Or during the process of syncing purchase orders to your QBO account? Any additional information would greatly help me provide you with a suitable recommendation to fix the issue.

Feel free to get back to me anytime. I'm determined to help you get this sorted out as soon as possible.