In order to get notified whenever a channel has a new video I have implemented the Pubsubhubbub protocol as suggested here: https://developers.google.com/youtube/v3/guides/push_notifications
The server I have for the callbackUrl is a Node.js application and I use the "pubsubhubbub" package to bootstrap the creation and handling of any events. But for whatever reason, the server doesn't receive any more requests. I've tried resubscribing to the YouTube channels but to no luck. Is there an expiration date after which all subscriptions are dropped so that I need to re-subscribe regularly? Any help would be very much appreciated.