I can't access the website because it's using HSTS and my browser says their certificate is invalid. There is no option to bypass the browser security warning. I'm at a public library. Anyone know what's going on?
Cisco Umbrella seems to be some type of security product for networks. Are you using a computer belonging to your employer or with employer software installed? They could be MITMing you. It seems odd that the Tor project would be using a Cisco product like that.
OpenDNS/Cisco Umbrella is basically a DNS-level security service that analyzes your DNS queries, blocks known malware domains, etc.
For some high-risk domains - depending on some settings - it will also switch to MitM'ing the connection to take a closer look at the traffic and block it on that level if necessary. It might also just be necessary to show the "This domain is blocked" page when you're requesting a site via https. Usually, your employer would pre-install their CA certificate, which would bypass the HSTS warning, but I suppose this might be a BYOD setting (or they just forgot/didn't like the idea of Cisco being able to MitM all the things).
Are you using firefox? I had an issue recently where my max tls version had been set to 1. Min version was also 1, max is supposed to be 3. Check about:config.
