There are two cases where you can come across the error The quantity must be a valid number greater than 0 when creating a listing for an item on eBay even though the available stock level is above 0.

1. The quantity for the listing is taken from the wrong location.

It may be that the location that has the intended stock for the item has not been enabled.

  1. Go to Settings > Channel Integration > click on the Location Mapping icon  
  2. Check all the needed locations are enabled.


2. The End When quantity for the channel or item is higher than the available level for the item. 

For example, you have End when set to 10 there are only 8 items left in your location. In this case, the system will not be able to create the listing and following error will be shown:

  1. Go to Settings > Channel Integration > click on the Edit channel details icon  
  2. Check the value under Inventory > End When.

If the value in channel settings is not problematic, the item-level value needs to be checked:

  1. Go to Settings > Channel Integration > Inventory Mapping  
  2. Click on the cog icon > choose column > and tick the End When column to make it visible.
  3. Find the SKU in question and check the value in the End When column for the SKU.

Listing an item with stock level below default End When value

There are situations where you may need to create listings for items, which are exceptional and have a stock level that is below your channel End When value. 

Even when adding an item-level value for the items that would be suitable for their current stock level, you are still receiving the error the quantity must be a valid number greater than 0.

This is due to the order or values that is submitted to the channel from Linnworks during listing creation. The following steps provide a workaround to create any listings for such items if you do not want to change the channel default End When value:

  1. Add item-specific End When values to the SKUs either manually on the channel mapping screen or via import.

  2. Add an Extended Property using any of the methods listed here to each of the SKUs, with the following format:
    • Property Name: MIN_LISTED_QTY_SubSource e.g. MIN_LISTED_QTY_EBAY0
    • Property Value: 1
    • Property type: Attribute

  3. The listing will now be created with a stock level 1. Once there is a stock level change, the correct quantity is submitted depending on the End When value you have added to the SKU on an item-level and the channel default End When value will not affect the listing anymore.