Why can't I remove download devices from Netflix?

To download something on another device, I tried to remove a download device from Netflix's website. However, that does not work, there's always an error message: "Unfortunately something went wrong. Please try again later. "I've just deleted all the downloads on a device, it will not be registered at all." What can I do to download something with another device?

Aufm device with the downloads delete everything. Or log out of all devices (you can do it via PC, in the account settings) and restart Netflix.

Did I try everything…