Every alert we send – and every alert we deliberately do not send – is a row in Settings → Alerts → Alert history (the site page shows the latest ones). Look for the status:
- Suppressed – maintenance: a maintenance window was open.
- Suppressed – quiet hours: your personal channel was in quiet hours.
- Suppressed – not in plan: the channel type needs Pro.
- Suppressed – provider not configured: SMS/Telegram is not set up yet.
- Failed: the channel rejected the message – the error is shown; fix the address and use Send test.
No row at all? Then nothing was confirmed: check the monitor's recent checks – a single failure or a local failure seen from one node only never alerts.