Check your email and ensure that you received an activation email containing the activation link. Follow the instructions to activate your account and then login to the website.
Please note that it may take several minutes for your confirmation email to arrive from from firstname.lastname@example.org. You may need to check your junk or spam filter mailbox for the activation email.
If you never receive the activation email, please try using an alternate email account to register your thermostat. If you register with an alternate email and are still unable to find the activation email, please call Honeywell's Customer Care at 1-855-733-5465.