If you already have a Rythm account but see a checkout prompt after logging in, you may be signed in with a different email address.
To access your existing account:
Select Back to Details in the upper-left corner.
Sign out.
Sign back in using the email address associated with your Rythm account.
Once you’re signed in with the correct email, you should be able to access your account as usual. If you still see the checkout prompt, contact customer support for help.