Brief comment till the morning: I would

1. Completely power down the Envoy - both mains and battery. Give it a
good rest overnight;

2. Power up again in the morning. If you can re-establish contact with
the Envoy then that check date and time, not forgetting year, are all
synchronised with PC!

3. If still no joy then move the logger to your main console, if
feasible, and see how that goes. At least that might tell you whether
it's the logger or console that has a problem.

John Dann
www.weatherstations.co.uk