Safari can't connect to the server on Mac

Safari can't connect to the server on my MacBook Pro. It will connect to apple.com, google.com, and a few other select websites. However, I'm unable to visit the majority of the websites I visit on a frequent basis. This problem does not exist on my iPad Pro.

Your thoughts?

I have already followed the following suggestion:

1. In the Safari app  on your Mac, check the message that appears when a page fails to open.
2. It may suggest ways to solve the problem or include information you need to solve it.
3. Make sure you’re using the correct address for the webpage.
4. If you copied and pasted the address, make sure it doesn’t have extra characters or missing characters at the beginning or end.
5. If the website requires a VPN connection, make sure it’s functioning properly.
6. See Connect your Mac to a VPN.
7. Try entering /index.html or /index.htm at the end of the address.
8. Choose View > Reload Page.
9. If the page still won’t open, quit Safari, reopen it, then try again.
10. Try again at a different time.
11. The website server may be busy, or the website may be unavailable temporarily.
12. Contact your network administrator for help.
13. If you connect to the internet using a corporate or enterprise network, the network may have a firewall that prevents you from opening the webpage.
14. If your computer or network is protected by a firewall, you may need to specify proxy servers to access some internet sites. 
15. See Set up a proxy server using Safari.
16. Contact the website’s owner to find out if the web server has a problem, or if the website is incompatible with Safari.
17. For example, Safari can’t open a website that uses a protocol other than http or https.
18. Choose Apple menu  > App Store, then click Updates.
19. Use the latest version of Safari. See Keep your Mac up to date.
20. Click and hold the Reload button , then choose Reload Without Content Blockers.
21. The page might be blocked by a Content Blocker you have installed.