I have just migrated from back up of my 2011 iMac to new 2019 iMac. When I open Facebook it opens to a page with one persons posting. When I try any of the clickable links on that page they open to blank pages. When I use Safari all is working as normal. I have Firefox 79 and Mac OSx 10.15.6. I have tried starting Firefox in Safe Mode to no avail. I have also done a reset to default settings but again no avail.