You attempted to reach www.youtube.com, but the server presented a certificate signed using a weak signature algorithm (such as SHA-1). This means that the security credentials the server presented could have been forged, and the server may not be the server you expected (you may be communicating with an attacker).
this pops up every time I try to reach google, facebook and ironically some opera websites etc. I unchecked TSL 1.1, 1.2 from the internet options still nothing. The only thing that helps is uninstalling opera with all client information and installing older version. I run on windows 8.1