CPU load graph is not showing for some machines.

Few graphs like cpuUsage, loadAverage, memoryUsage  are not being displayed
on the browser for couple of machines . I am not sure if it is
configuration problem because i have not admin password for cacti. Some
machines are displaying 23 graphs including mentioned graphs but some are
displaying 20 . It is clear that cacti is working for machine but not
showing only 3  graphs. I may need to configure on server side but i am not
sure. I never worked on cacti before. Can anybody help me to diagnose this.

Thanks,
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