Device was offline for two days, missing all graph data

I had a device go offline two days ago due to power loss at a site. The device is back online and I see new/updated data usage in the Overall Traffic graph, but all historical data for this device is gone/missing.

Is there anyway to get the historical Overall Traffic data back? Obviously I don’t expect there to be anything during the two days the device was offline.

Thanks.

did you set any thing here, that is the only thing comes to my mind

I have not modified any settings under cleanup. The current setting for that row is 0 and the row is grayed out. In your screen shot is it not grayed out.

Thanks.