Netflow active flow timeout?

I have set up a netflow sensor in PRTG to receive data from XG firewall. Does anyone know what the Active Flow Timeout setting should be on the PRTG netflow sensor? 

I am receiving the following error message from PRTG: "The NetFlow sensor has received and dropped flows with a timestamp older than the timespan defined by the active flow timeout. Ensure the active flow timeout from the sensor settings matches the flow timeout set in the flow exporter device."