When attempting to run a provisioning step in Quick Connect, the following error is seen:
An exception has occurred while executing 'PowerShell script'
script excution exception
You cannot call a method on a null-valued expression.
Examine the Connection Handlers on the connection, and the Step Handlers on the synchronization step, to see if any PowerShell is being run which is not needed or which is not correctly formatted.
Also check under Provisioning Rules | Initial Attribute Population Rules to see if any attributes are being generated via PowerShell which is not needed or which is not correctly formatted.