Continuity check....

We can argue this until the cows come home. You can even check continuity "the dangerous way" with a 120V light bulb.

Or if you are "not so dangerously" suited, use a battery and the biggest 12V bulb you can find......stop lamp or fog/ head lamp

I would start by.........

isolating all connections on both ends of the wire

Check each conductor "to ground" meaning "real" ground.......the grounding wire, not neutral. Also check neutral to ground

This will prove that there are no leaks 'to ground'

Also, check each wire to all the others, to prove there are no shorts to other conductors. This again, is will all (8?) connections open, unconnected (ground, neutral, hot and hot)

then twist any two together. This can be the two hot, or a hot and neutral. Check continuity.

Using a 120V or 12V bulb will get some current through there and hopefully show that the conductor isn't broken/ damaged, and just "touching" down there

Last I would do a resistance check between any two, one pair at a time. All/ any combo should show about the same......very low.......resistance.