You may run into FTL being offline and the Web interface shows “Lost Connection To API” meaning your stats will not load.
You may simply be able to solve the problem by restarting FTL using one of these commands
service pihole-FTL restart systemctl restart pihole-FTL
You can also view FTL’s debugger using these instructions, which may offer some clues.
We generally want to know if FTL is not doing what it is supposed to, so if the above commands do not offer any solution or insight, please get in contact with us.