Only subscriptions purchased via the web browser can be canceled via the web browser.
If you logged into your account via a web browser when you originally signed up for a membership you have two options to cancel.
Option One:
Message customerservice@yes.fit leave your email address attached to your Yes Fit account and request the membership be canceled.
Option Two is:
Log into your account at https://yes.fit/
Click the sidebar menu
Click on your Membership
Click to cancel