Note: Please do not post Personally Identifiable Information like email address, personal phone number, physical home address, product key etc.
Product & version number: android
What is the error message you are seeing? I cant see the option of cancellation as per the help center
It sounds like you purchased your Norton subscription from the app store for your device. If so, you have to request the cancellation directly from that store.
For the Google Play Store, see this information. Learn about refunds on Google Play - Google Play Help
For the Apple App Store, see this information. If you want to cancel a subscription from Apple - Apple Support (CA)