LEGACY - How do I fix QuickBooks Online error: QuickBooks Online must be configured to track quantities

When you go to the Integrations screen and click on your Edit QuickBooks Online button and you receive the following screen:

This means that you do not have Manage Inventory turned on in your QuickBooks Online account settings

Enable inventory tracking

You must be subscribed to QuickBooks Online PLUS or better.

To enable inventory tracking, you can either turn on inventory tracking with quantity on hand.

Turn on inventory tracking with quantity on hand:

1. Go to Settings ⚙ on the Toolbar.
2. Under Your Company, choose Account and Settings (or Company Settings).
3. In the left sidebar, select Sales.
4. Select the pencil next to Products and services and mark the option Track inventory quantity on hand (Note: This will enable the new item type called Inventory item when selecting New under Products and Services).
5. Select Save.

Also, Make sure your Purchase Orders are turned on: