Does refreshing the page display current planes or does the refreshed page still display old planes?

http://frpi/dump1090/data/aircraft.json

Does this file change when you refresh it when the map isn't working anymore?

Can you show your fr24feed.ini (remove key)

cat /etc/fr24feed.ini

Also let's check which Raspbian you are using:

cat /etc/os-release | grep -i pretty

If you don't mind some branding, you can also use dump1090-fa, installation is also done via install script.
https://github.com/wiedehopf/adsb-wi...or-dump1090-fa