It's possible that a problem with Firefox is causing Facebook to not function correctly. This could be a missing or corrupt program file, or a problem with the Firefox settings. Download and install the latest version of the program from the official website at mozilla.org. This process will replace any files that have been erased or damaged, add the latest features and bug fixes, and improve compatibility with websites and other applications. If an update doesn't fix the problem, uninstall Firefox completely to remove all traces of the software before starting the installation process again from scratch.