I worked it out. I was missing the scope in my authorize call. If I change to https://mytenant.eu.auth0.com/authorize?client_id=abc123&response_type=code&redirect_uri=http://mydomain.com/index.php?auth0=1&scope=openid+profile+email
it works.
YAY!
I worked it out. I was missing the scope in my authorize call. If I change to https://mytenant.eu.auth0.com/authorize?client_id=abc123&response_type=code&redirect_uri=http://mydomain.com/index.php?auth0=1&scope=openid+profile+email
it works.
YAY!