and 
Luke 1977
2500000090929
Accessories
Casual
Gifts
Luke 1977
Nash Knitted Rib Beanie
You renderd the snippet swatch.liquid with the name of a product option — 'Size' — that does not belong to your product.
Use {% render 'swatch' with 'name of your product option here' %}
Example: {% render 'swatch' with 'Color' %}
This is case-sensitive! Do not put in 'color' if your product option name is 'Color'.