Privacybox.de is a good open source alternative if you need people to email you encrypted and they have no idea about encryption. You can forward it to a nym server or tormail, or just retrieve it from their i2p or tor hidden service though I don't trust tormail whatsoever it could disappear or go down at anytime and lose all your emails.

As for Jitsi from riseup.net "In the past, we have recommended that people avoid Jitsi. It had a flaw that made it easy for an attacker to force Jitsi to use unencrypted connections. Supposedly, this has been fixed, but we are not sure in what version."

According to jitsi-dev mailing list it doesn't work so well with a VPN either.