Hi Jerseypick, this usually is caused by a "man in the middle" intercepting your browsing and generating fake website certificates. Firefox may need to be set up to work with your security software, such as Avast, AVG, Bitdefender, ESET or Kaspersky. Here are our general support articles: * [[What does "Your connection is not secure" mean?]] * [[How to troubleshoot "Your connection is not secure" error codes on secure websites]] If you don't find the answer there, you can try to figure out what software is generating the fake certificates from one of the error pages. Click the '''Advanced''' button in the page to access more information about the problem, and click the SEC_ERROR_UNKNOWN_ISSUER link to expand a panel that (hopefully) shows a coded version of the certificate. You can copy/paste that large block of gibberish into a reply here and a volunteer can run it through a decoder to see who is listed as the Issuer. Or you can try it yourself on a site like the following (or others that are similar): https://certlogik.com/decoder/ Any progress?