This happens if a web page opens an external page in an iframe and the website prohibits this via CSP rules or via a X-FRAME-OPTIONS header in the HTTP response headers. You can right-click the frame area with the error message and use "This Frame: Show Only This Frame" or "This Frame: Open Frame in New Tab" to display this page.

Thank you, though I don't understand the technical details entirely. But my problem is with my own blog. I can view pages, but can't, for example, respond to questions because the page "can't be opened." I want to fix that part. I also wonder if I can find out where the page has been embedded externally. Thanks for any help.

If Firefox can't open a specific page, the issue could stem from several causes. Here's a troubleshooting guide to help:

1. Check Internet Connection Ensure that you're connected to the internet. Try visiting other websites to confirm it's not a general connection issue. 2. Clear Browser Cache Cached data can sometimes cause issues. Clear your cache by: Clicking on the Menu (≡) → Settings → Privacy & Security. Scroll down to Cookies and Site Data, and click on Clear Data. 3. Disable Add-ons Add-ons can interfere with certain pages loading. Try running Firefox in Safe Mode to see if it's an extension causing the issue: Click on Menu (≡) → Help → Restart with Add-ons Disabled. If the page works in Safe Mode, you can disable the add-ons one by one to identify the culprit. 4. DNS or Proxy Settings Check if the page might be blocked by incorrect DNS settings: Go to Menu (≡) → Settings → General → Scroll to Network Settings and click Settings. Ensure No Proxy is selected or, if using a proxy, that it's configured correctly. You could also try using a different DNS, like Google's Public DNS (8.8.8.8 and 8.8.4.4). 5. Check for Security Software Blocking Some security software, like antivirus or firewalls, can block certain websites. Disable the security software temporarily and try accessing the page again. If this works, you'll need to add an exception for the page in your security software settings. 6. Check for HTTPS Issues Some websites force HTTPS and may have issues with their SSL certificates. Try visiting other HTTPS sites. If the page is HTTPS, ensure your system time and date are correct, as an incorrect system clock can cause SSL verification problems. 7. Update or Reinstall Firefox If Firefox is out-of-date, it might not handle some modern websites properly: Go to Menu (≡) → Help → About Firefox to check for updates. If the issue persists, try reinstalling Firefox to reset any corrupted settings.

I did try steps 1-5. Have not tried #6, but this is not a general issue with Firefox (I see it on no other website) nor even with my blog, just with three recent blog posts. And as mentioned, those posts open fine with Safari. As for step #7, system tells me my Firefox is current, and was recently updated. I think the solutions suggested are global ones, and I don't think that my problem is that kind. I also tried looking at the offending pages on my wife's computer (she uses Thunderbird), and no problem there. Would still appreciate suggestions.

This is not a Firefox problem, so you can't do anything to fix this in Firefox.

I assume that you do get "This Frame" if you right-click in that area?

You can use the page inspector and possibly check the Web Console and the Network Monitor to see what is going on.

• https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/examine_and_edit_html/
• https://firefox-source-docs.mozilla.org/devtools-user/web_console/
• https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/