You are behind a SonicWall-brand firewall with Content Filtering Service.
The network administrator has enabled CFS and configured it to block certain websites.
You must contact the network administrator and request access to the blocked sites.
I have set up SonicWall CFS and you are not going to work around it.
There is a very slim chance that CFS was set up to only be active during "business" hours and may be inactive after "business" hours.
The only realistic choice is to find out if there is another way to get to the Internet. There may be a WiFi signal nearby that you can use to connect to the Internet. This would bypass the SonicWall.
I hope this helps.