Missing graph if traffic 400M+

[Burpees]

Hi all,
i have a problem with zabbix. I'm monitoring Mikrotik device via SNMPv2. If there is a traffic over 400Mbit/s, a graph isn't showing "bytes in". Do you have any ideas please?

In attachments you can find graph image, item prototype settings, zabbix server conf.

Thank you in advance.

[tcilmo]

It sounds like the device gets overloaded and can not process the requests from Zabbix and data is not returned for a while. A good test is when device gets over 400M, is to manually pull the SNMP data and see what happens.