Can't add new Notification Channels

I tried using some code from another thread in the forum to enable a Find My Phone function. The notification is received on my phone instantly, but when I then go into settings->Companion App->Notification Channels, the new channel I tried to define isn’t there. Have I misunderstood? Is there something else I need to do? The app is set to maintain a persistent connection on home wifi, if that makes any difference?

Here is the script code:

alias: Find Nicks Phone
  - service: notify.mobile_app_galaxy_s20
    metadata: {}
      message: Home Assistant is finding your phone
      title: Home Assistant
        ttl: 0
        priority: high
        Channel: FindPhone
        tag: find-me
mode: single
icon: mdi:cellphone-sound

make it lower case so channel: FindPhone

docs: Introduction | Home Assistant Companion Docs

Oops! Thank you.