Setting up Rapid SSL certificates

I bought a ssl certificate on Rapid SSL and I followed the guide like 'ngnix' server which means I bundled my server certificate (from my mail / account 'Web Server CERTIFICATE' ) and the intermediate certificate ( from my mail / account 'INTERMEDIATE CA CERTIFICATE' ) into a .pem file. I set as chained file and restarted openlitespeed. It was working ( I thought ) but it doesn't seem to work.

When I used the RapidSSL Installation Checker, i can see the status 'Successful'
When I'm accessing with a real browser like firefox or chrome nothing's showing up -> Error Code: ERR_SPDY_INADEQUATE_TRANSPORT_SECURITY. With safari i can access but actually when I cleaned and check the certificate confirmation again, it doesn't prompt all the informations (intermediate, etc... )

Any idea please ? Should I somewhere package the Geotrust / Rapid CA too ? Any help would be greatly appreciated