When I search for this problem on the web, it seems sporadic, with users asking whether it is caused by cap on usage or other issues. If you use SuddenLink as your service provider, you might need to inquire with them. ---- But more generally speaking, there should not be unofficial certificates for Google and Bing. Can you check: (1) Do you use any special connection services, such as a private VPN or TOR? You could double-check your Firefox connection setting here: orange Firefox button (or Tools menu) > Options > Advanced > Network mini-tab > "Settings" button The default is to share your IE connection settings ("Use system proxy settings") but you can try "No proxy" to see whether that makes a difference. (2) Do you get the same error in Firefox's Safe Mode? This is a quick way to rule out extension issues, since they are deactivated in Firefox's Safe Mode. You can restart Firefox in Safe Mode using Help > Restart with Add-ons Disabled ''(Flash and other plugins still run)'' In the dialog, click "Start in Safe Mode" (''not'' Reset) Any difference? ---- If neither of those makes a difference, you may have one of the following issues: (1) DNS service provider error<br> (2) DNS hijacked to unexpected servers (either in Windows or upstream in a wireless/wired router, or in a cable/DSL modem)<br> (3) Malware