[ArcadeQuarters]

While this specific error is probably unrelated, you should also not blindly trust Firefox (or any other browser):

According to a top-secret NSA presentation provided by the whistleblower Edward Snowden, one successful technique the NSA has developed involves exploiting the Tor browser bundle, a collection of programs designed to make it easy for people to install and use the software. The trick identifies Tor users on the Internet and then executes an attack against their Firefox web browser.

https://www.schneier.com/blog/archives/2013/10/how_the_nsa_att.html

[null and void]

I don't think I use Tor. Probably do through StartPage though.