In some cases, your browser (Chrome, Firefox, Internet Explorer, etc.) will save log in information from when you have signed in to Ad-ID previously and may be automatically logging you in. This can cause issues with trying to reset your password or creating a new profile if you need to set up a different email address.
To resolve the issue, you should try clearing your browser history, including cache. Each browser will have somewhat different steps on how to do this. Or you can try using a different browser that you may not have used to log in to Ad-ID previously.