QB Issue Resolution:

To set up classes with QB Online you need to make sure the preference is enabled. To do this:
•Click the Gear icon in the upper right.
•Select Company Settings from the drop down window.
•Once on the Preferences screen, select Categories from the list on the left.
•Here you should see the options for Location/Class tracking. Put a check mark in the check box next to Class tracking and click Save at the bottom.

Resolution for Issue 'How do I setup a Class in QBO?' available: Yes (Solved).
Source: Intuit Community forum.

How do I setup a Class in QBO?: this issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the issue yourself by looking for a resolution described below. If it is a complex issue or you are unable to solve the issue, you may contact us by clicking here or by using other support options.

Support for Class
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