secure connection to website

Hello lain ellis,

Thanks for that info and for choosing the Apple Support Communities. If we understand correctly, you are unable to open specific websites on your Mac mini. First, let's see if the steps in this Apple resource helps with your situation: If Safari on Mac doesn't open a webpage or isn’t working as expected - Apple Support

"Check Safari extensions

If you installed any Safari extensions, make sure that they are up to date.

You can also try turning extensions off. From the menu bar in Safari, choose Safari > Settings (or Preferences). Click Extensions, then deselect the checkbox for each extension to turn it off. Learn more about Safari extensions. 

Check Safari settings

The webpage might not be compatible with one or more browser settings, which you can turn on or off as needed. From the menu bar in Safari, choose Safari > Settings (or Preferences). Then click Websites, Privacy, or Security to access these settings:

• Websites settings. These settings can be configured for specific websites.
• Privacy settings. These settings apply to all websites.
• Security settings. These settings apply to all websites. 

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 it in a private window. From the menu bar in Safari, choose File > New Private Window, or press Shift-Command-N.

If that works, use the following steps to remove the website's data, including its caches and cookies. 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.

1. Choose Safari > Settings (or Preferences), then click Privacy.
2. Click Manage Website Data.
3. Select the affected website from the list shown.
4. Click Remove.
5. Click Done.
6. Open the website again in a non-private browser window.

Install software updates

Install all available Apple software updates, which can include updates for Safari.

Check VPN or other security software

If you installed VPN or other software that monitors or interacts with your network connections, that software could affect your use of the website or the internet. Learn about network issues related to VPN and other software. 

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.

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

Resolve other issues

• If Safari appears to be stuck on an unexpected homepage
• If you want to block pop-up ads and windows
• If you deleted Safari and don't have a backup, reinstall macOS to put Safari back in your Applications folder. Reinstalling macOS doesn't remove data from your computer."

Next, use safe mode to start up your Mac as it does the following things:

• Verifies your startup disk and attempts to repair directory issues, if needed
• Loads only required kernel extensions
• Prevents Startup Items and Login Items from opening automatically
• Disables user-installed fonts
• Deletes font caches, kernel cache, and other system cache files

Log in to your user account and test the issue while in safe mode and then restart normally and test the issue again.

How to use safe mode on your Mac - Apple Support

Cheers!