PRTG - Network Bandwidth display wrong info

We have installed PRTG datasource (PRTG API version: 20.2.59.1689+) into Grafana version v7.1.3 (5723d951af). I am able to see the PRTG data in Grafana. However the traffic information (bandwidth) seems displaying incorrectly. I am unable to see the unit as Mbps on Grafana. Please kindly advise.