i've a problem with server statistics in multi server environment, when i go on Monitoring > Server statistics for all tabs instead of all charts the interface show "no data available"

On the server running logger service i've recreate the statistics with this commands but the problem persists:
HTML Code:
su - zimbra
zmloggerctl stop
rm -rf /opt/zimbra/logger/db/data/*
/opt/zimbra/libexec/zmfixperms (as root)
/opt/zimbra/bin/zmsyslogsetup (as root)
zmloggerctl start
Can anyone help me?