"Add a Variation using Variation Wizard" not working?

When I clicked on “Sell Yours” in the Existing Child Variation Section, I entered the condition, quantity and price. After I clicked “Save”, it wasn’t saved?! I had refleshed the page and retried it couple of times and it still not saved. Do I have to wait for 15 mins or something? But it worked immediately when I add a particular size of a product listing by using “Add a Product”.
Please advice if I missed something, many thanks!