This can occur when you have TLS disabled or set too high in your Firefox settings. A work-around is to use Chrome or perform the following:
security.tls.version.max. (double-click it and change its value to 0)
Another possibility is you are going through a proxy which does not allow for TLS / SSL in some situations. Contact the system administrator of that proxy. If your Firefox is set to a proxy and you do not use one, go to Tools > Options > Advanced > Network : Connection > Settings If you do not need to use a proxy to connect to internet then try to select "No Proxy" if "Use the system proxy settings" or one of the others do not work properly.