I am trying to complete Trail Head modules, but the site will not let me do so and keeps routing me to sign in using a developer account. When I try to create a developer account at the bottom of the page when it asks me to create a username, no matter what email I use (my company email address- IbeA@incapsulate.com or my personal email address- Annegelica.Ibe@gmail.com), it states that an account with this email is already in use.  Can anyone help me? I tried opening a case with Salesforce but they told me to just post my question/issue on this forum.