Centos 6 with Webmin/Virtualmin and Apache:
I tried out the new letsencrypt feature for my virtualhost and initially it failed. After some searching I found that I needed to install python-argparse, after that the lets encrypt tab on the SSL management page for my virtual host worked and setup my vhost with a cert from Lets Encrypt! Great… works fine in Chrome. But… Firefox doesn’t like it and the tester at ssllabs.com that analyzes certs gave me a grade C.
Virtualmin SSL setup vulnerable to poodle, no perfect forward secrecy… I was able to fix all that by tinkering with the directives…
But I cannot for the life of me figure out why firefox still doesn’t like the cert and I get "This server’s certificate chain is incomplete. Grade capped to B. " at SSL labs. - Everything appears to have worked correctly getting the Let’s Encrypt cert installed. My CA tab shows “Let’s Encrypt Authority X1…”
Any ideas on how to fix this chain issue?