Web search: https://www.bing.com/search?q=SEC_ERROR_BAD_SIGNATURE Web search: 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 There can be two possibilities: one is that the server is outdated and doesn't support modern cipher suites, another might be that the server only supports a few cipher suites and Firefox doesn't support any of these.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

Do these websites support a secure HTTPS connection ? Can you post a link to a publicly accessible page (i.e. no authentication or signing on required)?