This pop-up message means that we are able to find an account already connected to that email. It is also an indication of that you are not on the login page but on the page where you register a new account, this is not possible as the email address is already connected to an account.
TWO SOLUTIONS:
1. Go back to the first screen that you get to when opening the app and press Log in instead of Get started.
2. Enter another email that you have that has not yet been connected to a Lifesum account.
If none of these steps work, please reach out to us here. We can either help you reset your password etc or help you delete the old account if you reach out from the connected email.