Problem VLAN reading on SMNP PRTG

Hello Good Morning!
I have a pepelink Model: Peplink Balance 20

Firmware: 8.1.1 build 4986

I want to know how i can set a prtg sensor on a VLAN that i created …
i set everything ok, i can see all LANS / WANS but vlans dont show to me. I am trying to monitor through PRTG.
Can you guys help me what i have to do to solve this?