Graphs are stopping after a While.

[rbr4g4]

Hello every one.
I'm working with Zabbix 3.0.1 on Ubuntu.
I'm trying to monitor the traffic of my firewall by SMNP.
The hosts are connected OK (Green on SNMP Pic)
My problem is that just after I restart the apache server, then shows the graph for around 10 minutes, and after that nothing more.

Thank in advanced for any help

[rbr4g4]

Solved

I found the problem
Just uncheking (Use bulk requests)

Thanks