Z-EndStop Always Activated

The printer that I use has worked fine for roughly a year before suddenly the Z-axis refused to lower under any circumstances. After manually lowering the axis and trying again, I repeatedly saw the console entry “echo:ZEndstop: [the current Z axis height]” Which indicated to me that the Endstop was constantly activated and would not allow the assembly to lower.

I have isolated the brown cable from the assembly and used a multimeter to check the connection between the terminals, which gave a positive connection, but not from the terminal to the wire. I then took out the female end of the cable and used a small piece of wire to test the connection between the two wires, which worked as it should. There seems to be no shorting issues in the wire itself and the main problem appears to reside in either the Endstop, or mainboard, as even when unplugged the Z-Endstop seemed to be active and prevented downwards movement. Would this be caused by another port or sensor?

Any feedback is welcomed.

You should check the switch for continuity.
When the Z axis is in the home position the switch (outside poles) should be open.
When the Z axis is away from the home position the outside poles should show a short