Variations Dropdown not showing

I am trying to make a very straightforward variable product (a t-shirt with various sizes) and I am not able to make the size drop-down menu show up on the product detail page. I have followed several guides on how to make a variable product on Woo-Commerce and I believe now that the problem is somehow related to a bug in the code, because the <table></table> element is created, but there is no content inside.

Any and all help would be vastly appreciated. Thank you!