According to ssllabs.com SSL OCSP stapling is not enabled, even though I have the following in my http block:

ssl_stapling on;
ssl_stapling_verify on;
ssl_trusted_certificate /etc/pki/tls/certs/ca-bundle.trust.crt;
resolver 8.8.4.4 8.8.8.8 valid=600s;
resolver_timeout 15s;

Any idea why? Here is my full ssllabs.com report: https://www.ssllabs.com/ssltest/analyze.html?d=commando.io