Introduction When the Datadog agent stops sending metrics, monitoring blind spots emerge. This can be caused by API key issues, network problems, or the agent itself crashing.

Symptoms - Datadog infrastructure list shows hosts as "not reporting" - Metrics gap in Datadog dashboards - Agent status shows "Not running" or "Connection failed" - Error: "API key is invalid" in agent logs - Agent process consuming excessive CPU/memory

Common Causes - API key expired or revoked - Network connectivity blocked to Datadog endpoints - Agent configuration file corrupted - Agent version incompatible with Datadog API - Proxy configuration blocking outbound traffic

Step-by-Step Fix 1. **Check agent status**: ```bash datadog-agent status # Or systemctl status datadog-agent ```

  1. 1.Verify API key is valid:
  2. 2.```bash
  3. 3.curl -X GET "https://api.datadoghq.com/api/v1/validate" \
  4. 4.-H "DD-API-KEY: <your-api-key>"
  5. 5.`
  6. 6.Test network connectivity to Datadog:
  7. 7.```bash
  8. 8.curl -v https://api.datadoghq.com/api/v1/validate
  9. 9.curl -v https://agent-intake.datadoghq.com
  10. 10.`
  11. 11.Restart the agent:
  12. 12.```bash
  13. 13.systemctl restart datadog-agent
  14. 14.datadog-agent status
  15. 15.`

Prevention - Monitor agent health with Datadog's own agent check - Set up alerts for hosts not reporting - Rotate API keys before expiration - Test agent connectivity after network changes - Use Datadog Agent v7 with improved error reporting