This problem is happening because we do not have a default category for the store view.
Go to Magento Backend > POS > Manage Location > open 1 location
Link your primary location to a store view
Edit the above Store View and Set Root Category for this Store View
Remember to enable that Category if it is Root Category
Step 2: Edit the above Store View
Step 3: Set Root Category for this Store View
Step 4: Remember to enable that Category if it is Root Category