2020 MacBook Air not loading webpages when connected to WiFi

1. Rule out the WiFi

• Restart your Router
• Check if other devices on the WiFi work properly

2. Check the Macs IP Settings (System Preferences, Network)

• Select WiFi network and click "Advanced...", under TCP/IP IPv4 should be "Using DHCP" and IPv6 should be set to "Automatically" (unless of course, your Router is configured otherwise)

3. Try an alternative DNS server

• In the same panel as before, select DNS, click the + and enter "1.1.1.1" (the public DNS from Cloudflare)

4. Check with a new "Location" (close the WiFi pane, on the top of the network preferences click "Location", "Edit Locations...", create a new one and switch to that, then join the WiFi again

5. Empty the DNS cache using Terminal:

• dscacheutil -flushcache;sudo killall -HUP mDNSResponder

6. Check for Malware

• Check Startup items in System Preferences, Users & Groups, , Login Items)
• Check Launch Items (~/Library/LaunchAgents, /Library/LaunchAgents, /LaunchDaemons/) for unknown software
• Use a tool (such as MalwareBytes)

These solutions are appropriate for issues that affect Safari on Mac, including issues such as the following. Before you get started, make sure that your Mac is connected to the internet.

1. A webpage is blank or doesn't show all of its content

2. You can't to sign in to a webpage, despite using the correct sign-in information

3. A webpage asks you to remove or reset cookies

4. Safari slows down or stops responding

Reload the page

If a page doesn't open or finish loading, try to reload it: Choose View > Reload Page or press Command-R. If that doesn't work, press Command-Q to quit Safari, then reopen Safari and try again. If Safari doesn't quit, press Option-Command-Esc to force Safari to quit.

Install software updates

Install all available Apple software updates, which can include updates for Safari. If you installed any Safari extensions, update them as well. 

Turn off Safari extensions

Even if your Safari extensions are up to date, temporarily turn them off to be sure they aren't affecting Safari in unexpected ways. Choose Safari > Preferences, then click Extensions. To turn off an extension, deselect its checkbox.

Test with a private window

A website can store cookies, caches, and other data on your Mac, and issues with that data can affect your use of the website. To prevent the website from using that data, view the website in a private window: Choose File > New Private Window.

If that works, use the following steps to remove the website's data from your Mac. The website can then create new data as needed. If it's a website that you sign in to, make sure that you know your sign-in information before continuing.

Check network settings

Certain network settings, such as those related to using a proxy server or custom DNS server, can affect access to content on the internet. Even if you haven't changed your network settings, you might have installed software that changed those settings for you.

To find out whether the issue is with the network settings on your Mac, try viewing the website from some other device connected to the same network. You can also add a new network location in Network preferences as a way to quickly reset your network settings for testing.

To find out whether the issue is with your network itself, try viewing the website after connecting to a different network.

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