It's impossible to authorize a display after registering with the API

it’s impossible to authorize a display after registering with the API, it returns me a 404.

That’s because it isn’t POST call ie the route you’re trying to reach does not exist, therefore 404.

Please see https://xibo.org.uk/manual-tempel/api/#/display/displayToggleAuthorise

Thank you very much for this very fast response.