Today's Plan versus Stages-Link

I’ve got an existing account with Stages-Link from my power meter. Today’s Plan is apparently affiliated with that service. Whenever I try to either log in or sign up for Today’s Plan through the Zwift link(s), I am redirected to my Stages-Link account page. I don’t see any of the Today’s Plan features or charts/tools available there.

Is there some trick to getting into the Today’s Plan features? Do I have to set up some throwaway/dummy email account?