try using a VPN just to confirm its not your IP address thats blocked from those sites.   use Opera Browser, turn on the VPN feature and try accessing the two sites again.  if you manage to connect to them, then its your IP address/ISP being blocked or a network routing issue.
I have a  Dell Precision 7550. It will not open some websites. I have done virus and malware checks and nothing was detected. I did a manufacture restore and I am still having the same problem. I use google chrome but I tried firefox and Microsoft edge too.  
Problems loading websites