Icinga2 PNP no perfdata service

Hi,

I am new to monitoring.
I have installed Icinga 2, Icingaweb2 and PnP in Ubuntu 18.06.

I have made everything work, except the graphics of the services. They appear empty. Within the folder where the information is collected to plot, perfdata, the rrd files have been created, although they are not updated or are updated intermittently.
The graphics belonging to the hosts work correctly.

For example, one of the hosts is checked by ping4, and the graph is correctly observed. In contrast for an X service, the ping4 check is not plotted (it appears empty).

The question is what could be happening?

I appreciate your time. Sorry for my English.

Thank you.

Please verify that the checks without graphs have valid performance data. For details please take a look here.