When working behind a SSL proxy, the SSL proxy presents another SSL certificate. When not using that certificate, the DOI fetcher returns "Connection error" without any further information:

IMHO JabRef should offer the possibility to:

• use an own key store
  • activated through preferences
• import .cer files into that key store
  • possibility offered using the preferences

See https://stackoverflow.com/q/18889058/873282 for some code hints.

Somehow refs #7627. Here, we have an SSL certificate issue. There, we have a proxy authentication error.