The graphs should appear, even if empty. Boxes at the top of the page have values.
Boxes have a spinning loading icon, it never finishes loading. Boxes at top of the page have no totals
v47mfg2e3n
Can you access the data trough the API URL? Maybe a server reboot / re-run the install script?
API URL: http://YOURIP/admin/api.php?summary
Will try a reboot again. -- Edit: No change after reboot
Results of going to the URL you suggested.
{"domains_being_blocked":"107,232","dns_queries_today":"3,322","ads_blocked_today":"176","ads_percentage_today":"5.3","unique_domains":"502","queries_forwarded":"1,789","queries_cached":"1,357","clients_ever_seen":"6","unique_clients":"6","status":"enabled"}
After reboot, it still shows the above stats
Okay looks like the core is working than and is producing data I think. 
Is it working if you open the admin panel URL with the browser on your smartphone (aka some other device)? Might be something browser / anti-virus related blocking the charts to load.
Do all three of these commands return data?
echo ">ForwardedoverTime" | nc 127.0.0.1 4711
echo ">ClientsoverTime" | nc 127.0.0.1 4711
echo ">QueryTypesoverTime" | nc 127.0.0.1 4711
Have you tried a force-refresh of your browser? Try Ctrl + F5