Please dig out the info requested in philipp's post as the next step: I'm confident we can get your Firefox working if you help us identify the source of the problem. Edge, IE and Chrome share the Windows certificate store, so whatever was necessary to set up one to trust the fake certificates works for all of them. You wonder: why only Firefox? Firefox uses an independent certificate store, and needs to be set up to trust fake certificates of the kind generated by certain security software and by 'man in the middle' malware. Since it is neither practical nor safe to make exceptions for fake certificates for the numerous additional servers used by popular sites the core task is to figure out why Firefox is raising these objections. com but eBay uses additional servers for critical content of the pages (e.g., ebaystatic. The key thing is you made an exception for a fake certificate for, I assume, ebay. I have attached a screenshot of how Faceook looks once you bypass that error, it is basically just text, why dont any of the graphics or images load?

Connection not secure error firefox