You can change your password using the Log In screen's Forgot your password? function. Enter your email and select Send Recovery Code.
Do not close the application at this time! The verification code will arrive in your email from email@example.com, and if the message doesn't appear in your email's Inbox, you may also want to check your spam and spam folder, as the message may sometimes be redirected there.
Enter the verification code and create a new password. Please note that the password must be at least 10 characters long and must contain uppercase and lowercase letters as well as numbers.
If you need any further help with this, don't hesitate to contact Firstbeat Support.