Invoke-WebRequest PowerShell Script won't run on Shutdown

Question

I've followed the directions at the bottom of this post on adding a Group Policy Shutdown PowerShell script, but it does not execute it during shutdown.

Run powershell script whenever a server reboot is initiated and show the script progress in cmd

When I run it manually, it executes correctly.

I think this has to do with it using Invoke-WebRequest in the script and perhaps the network connection is already shutdown before this script is executed.

I'm trying to turn off a Sonoff Switch running Tasmota. And as I said, it works properly when run manually:

$Response = Invoke-WebRequest -URI http://sonoff-magni.asgard/cm?user=xxxx"&"password=yyyyyyy"&"cmnd=Power%20Off

I've fully qualify the path to the ps1 script and even tried putting double-quotes around the path.

Still no joy. Any ideas?

Thanks!