Make sure you are not blocking content.

Start Firefox in Safe Mode {web link}

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

https://support.mozilla.org/en-US/kb/enhanced-tracking-protection-firefox-desktop

I'm afraid that didn't help. I attach a screenshot of what I see

Click on the lock icon in the URL bar and examine the certificate of this page.

Load the web page. Then, to reload the page bypassing the cache and force a fresh retrieval; Ctrl+Shift+R (Mac=Command+Shift+R)

Try this several times.

Thanks for the suggestions - they didn't fix it, but it has now fixed itself with a windows update!

Good to hear. Well done.

Oh no - the problem reappeared. However I tried the CTRL shift R mentioned above, and it fixed it. I hope this isn't a recurring problem.

Oh dear, it now seems to be a permanent problem. Ctrl shift R doesn't appear to do anything. Ebay still works fine on the microsoft Edge. What next?

Remove History For One Site {web link}

Open the History Manager <Control> (Mac=<Command>) <Shift> H. In the search bar, enter the name of the site. Right-click on one of the listings and select Forget About This Site. This should remove all information, including any site settings

A post was flagged as Solved Problem. If the problem is not solved, please remove that flag. If you don’t, others that can help may not read this post.

Go to that message, and use the Undo link to its right.

I'm afraid that didn't work either

Firefox shows a purple shield instead of a gray shield at the left end of the location/address bar in case Enhanced Tracking Protection is blocking content. You can click shield icon for more detail and possibly disable the protection. You can check the Web Console for messages about blocked content.

• https://support.mozilla.org/en-US/kb/enhanced-tracking-protection-firefox-desktop
• https://support.mozilla.org/en-US/kb/trackers-and-scripts-firefox-blocks-enhanced-track

That didn't help sadly. Now a new thing has happened! The ebay site loaded ok just now for the first time when I entered it manually, but if I try to laod using a link from elsewhere eg an email, it seems to be broken!

Start your Computer in safe mode with network support. Then start Firefox. Try Secure websites. Is the problem still there?

http://encyclopedia2.thefreedictionary.com/Linux+Safe+Mode Starting Any Computer In Safe Mode; Free Online Encyclopedia

Firefox shows a purple shield instead of a gray shield at the left end of the location/address bar in case Enhanced Tracking Protection is blocking content. You can click shield icon for more detail and possibly disable the protection.

Disabling helps. To be more specific, even setting the content blocking from "Strict" to "Standard" helps solving this. Now, I'd like to make this setting site-specific. Any ideas how to achieve that?

You can click the shield on the location bar with the strict list and check what eBay servers are blocked. Then you can create a cookie allow exception for these domain to see if that works.