You cant. They just shut down the server and removed the unlocker app from their site. Maybe, just maybe, they will release a “rewritten version” in the coming months according to some guy on xda who asked them.
This shit is the last asus product Im buying for a loong time if ever.
They’re actually continuing both phone lines. The long term support isn’t amazing but the zenphone line isn’t going away and will continue to be supported