Create you first Proxy, to translate http to https and to get around the mixed content error.
I stumbled upon a sharepoint.stackexchange.com problem where they had a problem when calling an http api in an https context. This resulted in an Mixed content error.
I solved this by creating an azure function proxy. To simply relay the request to the API and voila! No more mixed content error.
(I know this is maybe not the best approach to solve this issue. Should probably call the https endpoint from the getgo, but hey it's all about the hacks)