Hi JohnOzuk,
It could be because of intermittent network connection or could be server issue, since NPE is totally dependent on the network you would have faced this issue. Kindly run NPE again to see if the issue still occurs, if you still face the issue please send us NPE logs[etl file] stored in the below location for further analysis.
Log location:C:\Users\"current user"\AppData\Local\NPE\Tracesession.etl