This url: http://samples.libav.org/A-codecs/tak/
gets forwarded to this: https://samples.libav.org/A-codecs/tak/
However, that doesn't exist. Probably the rule for *.libav.org should be limited to libav.org and www.libav.org (and maybe others that work).
(P.S.: This is not the first time I see this - it seems you are too often making rules for *.domainname without checking if there are subdomains that don't support https. In doubt, I'd prefer limiting to rules that definitely work)