if the facebook feed won't render on your phone or tablet pr Mac using Safari browser:
The current problem is that your iPhone safari in the newest version of ios 15 has feature security on the Safari setting.
So because of that feature, You must check Privacy & Security on your setting safari.
Setting > (find) Safari > (find) Privacy & Security > (try to turn off) Hide Ip from Tracker.
then reload page and it should render properly.
Sorry for the inconvenience but this is beyond our control.