Make sure the machine is turned off and unplugged.

Set your voltmeter in continuity mode and place the leads on the two 90 degree prongs on the boiler's heating element.

It does not matter which lead touches which prong as you're just testing for a break, or "open" in the heating element circuit.'''

If the voltmeter shows 0, or "open", then there is an issue with the heating element's continuity and it needs to be replaced.

If given a reading, then your heating element is fine.