Percona Monitoring tool for Linux works from command line, do not show any graphs

I installed Percona Monitoring plugin 1.1 with Cacti 0.8.8f (latest).
I tested that it works from command line:

Reading Memory values
php /var/www/cacti/scripts/ss_get_by_ssh.php --host --type memory --items hq,hr,hs,ht,hu,hv
hq:441073664 hr:64520192 hs:274432 ht:189108224 hu:349212672 hv:1044189184

php /var/www/cacti/scripts/ss_get_by_ssh.php --host --type diskstats --device dm-1 --items iw,ix,iy,iz,jg,jh,ji,jj,jk,jl,jm,jl,jm
iw:31734 ix:0 iy:1426098 iz:83060 jg:13993 jh:0 ji:111944 jj:420965 jk:45727 jl:139208 jm:504025

Within Cacti I created graphs based on Percona GNU/Linux HT template for Centos 6.7 server, but nothing is showed in all these graphs.
I configured Cacti to access remote server via SSH, following steps described on Percona site, it works well.

Cacti works well for other graphs not based on Percona template, such as SNMP network interface, for locahost or for remote servers.

what’s wrong ?
How can fix it ?

thanks in advance
kind regards