Error: The template must contain a single auth0:head tag and at least one auth0:widget tag

Hey,

When I try to upload a custom login page (by using the APIs), I get the following error:

Error: 400 Bad Request: The template must contain a single auth0:head tag and at least one auth0:widget tag.

How do I update a fully custom page (i.e. without auth0: tags)?

I am able to upload this kind of page by using the GUI. Am I doing something wrong?

PS I have a free account therefore I will never be able to upload it, however I just need to understand how to prevent this “error”.