if you use wmi connection with impersonnation, you need to be connected as an domain admin on your workstation.

you should also change your code. You wrote :
$Service = GetObject("winmgmts:\\+$sComputer+\root\cimv2")

but it should be
$Service = GetObject("winmgmts:\\"+$sComputer+"\root\cimv2")
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Christophe