Please ensure you are trying to login to the online coaching website of SwimGym.com (see screenshot). The SwimGym pool website has a separate login.
For SwimGym.com login you need to enter the email and pasword which you used for setting-up your account. You can reset your password ("Forgot your password?")
IMPORTANT: in case you did not receive any confirmation emails of your purchased online membership, then it is likely you made a typo in setting up your account email address. Please contact SwimGym.com via the submit a request (you also find the link at the homepage of Frequently Asked Questions).