You can try to clear your Firefox cookies and cache: 1. Click on the menu button on the top right corner to open the menu panel. 2. Click History and select Clear Recent History…. 3. In the Time Range to clear: drop-down, select Everything. 4. Below the drop-down menu, select both Cookies and Cache. Make sure other items you want to keep are not selected. 5. Click OK.

Check for malware If clearing your cookies and cache did not enable you to load the websites that did not work in Firefox, you should check your computer for malware. Certain types of malware are known to target Firefox and can prevent it from loading various websites. If you have an antivirus or Internet security program, update its detections database and do a full scan of your system.

Check if an extension is causing the problem A Firefox extension could be causing the issue, especially the ones that have network access and/or those that rely on manipulating webpage content. Try disabling your extensions in the Add-ons Manager one by one and then reload the page.

https://www.bing.com/search?q=pr_end_of_file_error

radi.stoyanov said Turns out the option DNS over HTTPS is what caused the problem.

jamesafuf123 said https://support.mozilla.org/en-US/questions/1264659#answer-1237475 my ISP was blocking sites like that

cor-el said This usually means that Firefox wasn't able to find a cipher suites to use to connect to this server and reached the end of the list. There can be two possibilities: one is that the server is outdated and doesn't support modern cipher suites, another might be that the server only supports a few cipher suites and Firefox doesn't support any of these.

You can check your browser and possibly compare this with the server setup.

• https://www.ssllabs.com/ssltest/viewMyClient.html