The site is now part of machine ownership and should therefore be set together via machines/{machine_id}/ownership. That is why we now also offer a PATCH machines/{machine_id}/ownership so that the site ID can be changed.

We will allow the site to be set in the machine until April 6, 2020. After that, setting the site will only be possible in the ownership.

Further Reading: Zaikio Hub API Reference POST /machines/{machine_id}/ownership