Graphite - empty graphs

Hi,

My graphite charts stopped to fill up the charts with data, (The last data was in January; since then, there has been no data.) the only modification on the system was the usual security updates on my icinga server (Ubuntu).

On my graphite web:

On Icinga interface: (for every service, host I have no data in the chart)

Graphite version:
image

Icinga information:

Graphite and Icinga server OS:
image

The Icinga servers and the Graphite servers are installed on separate servers.