Troubleshooting

My notification isn't firing at all

In order of likelihood:

1. Is it active? Check the notification's active flag directly. Created with the active flag set to false and never turned on, or inactivated later — either way, dispatch skips it entirely, regardless of severity.
2. Does the check have a threshold or evaluator at all? See Before You Start — no threshold means the confirmed severity is permanently not_evaluable, which never satisfies any floor.
3. Was the check inside a blackout window? A 'run'-mode window records severity skipped with a blackout_id marker; an 'alerting'-mode window (the default) records the real severity with an alerting_blackout_id marker and reportable = false. Neither dispatches notifications — deliberately. The firing baseline reaches back past both kinds of marked rows to the last severity that was actually surfaced, which is what guarantees a check still breaching after a 'run' window doesn't spuriously re-fire, and a check that went critical inside an 'alerting' window fires exactly once at the first post-window evaluation. Check pghf.list_blackouts() and the evaluation's detail for the markers.
4. Is the check actually breaching at or above the floor, and is this a genuine transition? If it's been breaching for several runs already, that's expected silence — see Transition-Only. Check the evaluation history directly for that check, most recent first, to confirm what's actually happened.
5. Did you just activate the notification while the check was already breaching? That's the documented non-retroactive case in Managing Events — it'll fire on the next real transition, not immediately.
6. For 'notify' notifications: is anything actually listening on that exact channel name, in a session that's still connected? An unheard notification isn't an error and leaves no trace.
7. For 'function' notifications: check your logs for a warning mentioning the notification's identifier — the function may be firing and failing. Dispatch never lets that abort the run, so a failing function notification is easy to miss if nothing is watching for warnings.

My notification fired more than once for what looks like one breach

Confirm it's genuinely re-firing, and not two different notifications — for example, a warning-floor notification and a critical-floor notification both registered on the same check will both fire, independently, as severity climbs through both floors during one worsening trend. That's two notifications each doing their job, not one notification double-firing.

Continue to Worked Walkthrough.