New Snooze Trello PowerUp

Hi,

Attempting a Trello PowerUp.
I remixed the “Trello Card Snooze Power-Up” gitch.
I see the button and the date picker in Trello, but when I click snooze get 403 error:

/snooze? seems to be a missing resouce hence a 403 error.
Is this missing or am i expected to write?

A 403 is thrown in the /snooze route if the token supplied either isn’t valid or does not have access to the card in question. Please check your token and permissions. Thanks