If you have this error chances are you do not have a size type selected in Lightspeed.
Below is where you would put the size type desired in your custom fields area of Lightspeed.
Under that "Size Type" custom field you can select which size type this piece of clothing has. Once that is done save the changes in Lightspeed then perform the following
1. Login to Hyperspacecloud.com
2. Go to your eBay tab
3. Scroll to the bottom of the screen and click the green "+MORE" button.
4. Click the blue "LOAD INVENTORY" button
5. Wait for that process to finish (once done Hyperspace will now display all of your recent changes made to your products)
6. Find that product in the hyperspace eBay tab and then run a web-store sync selected on that product and it will turn green after the process finishes.