there currently appears to be no issues on the Websites-side. And we can access these websites using firefox. You can try the following steps however since the problem is not created by our side our ability to help is limited.
Clearing Browser Cache:
Go to the Firefox menu (three horizontal lines in the top right corner).
Select "Options" or "Preferences."
Scroll down to the "Privacy & Security" section.
Under "Cookies and Site Data," click on "Clear Data."
Check "Cookies and Site Data" and "Cached Web Content,"
then click "Clear."
Disable Extensions:
Sometimes, browser extensions can interfere with website loading. Try disabling all your extensions temporarily and see if the problem persists.
Go to the Firefox menu.
Click on "Add-ons" or "Extensions."
Disable or remove extensions one by one to identify if any of them are causing the issue.
Check Firewall or Security Software:
Your firewall or security software may be blocking access to specific websites. Review your firewall settings and ensure Firefox has permission to access the internet.
Try Private Browsing Mode:
Open a new private browsing window (Ctrl+Shift+P on Windows, Command+Shift+P on Mac).
Attempt to visit the problematic website in this mode to see if it loads.
Reset Firefox:
If the issue persists, you can reset Firefox to its default settings. This will remove your extensions, themes, and custom settings, so use this as a last resort.
Go to the Firefox menu.
Select "Help" > "Troubleshooting Information." Click the "Refresh Firefox" button.