Electricity is movement of charge.
In ionic conduction the charge is carried by ions. Ionic solids exist as a lattice of cations and anions.
At room temperature the ions are not mobile as they vibrate in position in the lattice.
As the video shows, in the molten solid, the ions have sufficient energy to move from their lattice positions.
This means that they can move toward electrodes in a cell. This completes the circuit and causes the bulb to glow. Thus ionic substances conduct electricity if they are molten.
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A substance conducts electricity if when placed between the electrodes in a circuit which includes a source of electrical current, the circuit is complete due to electricity flow through the substance.
In ionic conduction the charge is carried by ions. Ionic solids exist as a lattice of cations and anions.
At room temperature the ions are not mobile as they vibrate in position in the lattice.
As the video shows, in the molten solid, the ions have sufficient energy to move from their lattice positions.
This means that they can move toward electrodes in a cell. This completes the circuit and causes the bulb to glow. Thus ionic substances conduct electricity if they are molten.
 ionic solid does NOT conduct electricity |  molten ionic solid conducts electricity |