When you install the plugin in WordPress (Plausible 2.1.4 ) and want to set up community edition the domain name of plausible must be added without https
e.g. you enter: https://plausible.mydomain.com then when trying to create a token it'll open the popup as https://https://plausible.mydomain.com hence of course it won't work
Probably a validation or any kind of hint would help.