All you see at Reports->Dashboard is the following error message ...
There was an error collecting ganglia data (127.0.0.1:8652): fsockopen error: Connection refused
The most likely cause is that the colama server does not have a default route configured.
ganglia uses multicast for communication and multicast will not work without a configured default route.
Recommendation: (needs Administrative privileges)
configure a default route on the external interface and this problem will go away.
sudo route add default gw <gateway ip>
and restart the ganglia service
sudo service gmond restart
refresh the webpage
ctrl + F5