Certain site doesn't open in browser
Use Network Utility to look up the site:



Verify you can reach ports 80 and 443 (and only use http for when port 80 is open and https for port 443)



Then enter the IP address instead of the DNS name in safari (or whatever browser). If your DNS is not working on the Mac, you can get the IP from another computer and verify the rest of the Mac works and focus on DNS.