You have upgraded your ProxySG or ASG to SGOS 18.104.22.168.
Some sites are inaccessible after the upgrade.
You have tunnel-on-error enabled on the ProxySG or ASG appliance.
This is a known issue on ProxySG and ASG when proxying to SSLv2 and tunnel-on-error is enabled.
Currently, there is no solution other than to bypass SSLv2 sites from the ProxySG or ASG, or disable tunnel-on-error.
For more information on the tunnel-on-error feature see Tunnel on Protocol Error Feature usage in the ProxySG