To add a bit more info, I see your site is using a Go Daddy G2 (SHA2) cert. In that case, here is the intermediate/root chain you'll want to use as ssl_trusted_cetificate. C=US, ST=Arizona, L=Scottsdale, O=GoDaddy.com, Inc., OU=http://certs.godaddy.com/repository/, CN=Go Daddy Secure Certificate Authority - G2 C=US, ST=Arizona, L=Scottsdale, O=GoDaddy.com, Inc., CN=Go Daddy Root Certificate Aby djlarsu - Nginx Mailing List - English
This configuration is working for me. Perhaps nginx cannot verify the OCSP response with the bundle in /etc/pki/tls/certs/ca-bundle.trust.crt ? In my ssl_trusted_certificate file, I have these certificates, in order. C=US, O=The Go Daddy Group, Inc., OU=Go Daddy Class 2 Certification Authority C=US, ST=Arizona, L=Scottsdale, O=GoDaddy.com, Inc., OU=http://certificates.godaddy.com/repository,by djlarsu - Nginx Mailing List - English