Winding of the magnetic element is floating

Hello. I’m trying to run the Test circuit for measuring the B-H loop (Example B-H 3F3.sch), available in the examples, but it always returns an error message:

Element: MAG_WINDING Name: MAG_WINDING1
Error: The winding of the magnetic element is floating!

Can someone help me with this problem, please?

The circuit in question is in the figure below.