Create SKU via API

Hi Webflow community,

We’re trying to do a one-time sync from our current API to sync all products to Webflow. Creating the products with its default skus it self works like a charm, as you can see here:

But when trying to create a new SKU for one of these products we always get a duplicate error as following:

And when we manually create a new SKU (Size) like this:

And try to create a new SKU we get this error:

I’ve tried adding size: options etc, but nothing seems to work. How would we approach this? Can’t seem to find it out using the documentation…

I need this too someone help