An Event Grid subscription to an Azure Function endpoint fails consistently. Where should you first check for errors?

1. A Azure Monitor activity log
2. ✓ B Event Grid subscription Metrics (delivery failure metrics) and Azure Function logs (correct answer)
3. C Storage Account logs
4. D Network Security Group flow logs

Shortcut: Event Grid subscription metrics show delivery success/failure counts. Function logs show whether invocations occurred and what errors happened. Use Azure Monitor diagnostics logs on the Event Grid topic for detailed tracing.