I used  "Merchant Integration Platform"  (CSV) to create / add items in LISTINGS.

Then tried to edit the item in active listings.

After edited and clicked "Update Listing" button, it showed red error at the top:

It looks like there's a problem with this listing.

Inventory-based listing management is not currently supported by this tool. Please refer to the tool used to create this listing.

That means I cannot edit the item at all.

I have tried many differernt items, all got the same thing/error.

Can anyone help or advise?

Thanks.