What changed
A source that returns repeated errors gets flagged as unreachable on the Watchers page and stops being scheduled, with a Check again probe to retest on demand.
Why it matters
A subreddit going private used to fail quietly — your Watcher looked healthy while collecting nothing. Silent failure is the worst kind for a monitoring tool: you only notice when you needed the data and it wasn't there.
How to use it
Unreachable sources are marked on the Watchers page. Press Check again after a source comes back.