Z-axis moves in one direction (1 reply)

I have tested the motor and it is fine. Despite what g code I push to it, it will only move one way. I am using a RAMPS 1.4 with an Arduino Mega 2560. The stepper drivers are standard A4988. I have flashed it with Marlin 2.0 firmware. I have been working on this project for a week and I don't know what to do. This is not for a 3d printer, but a robotic arm. I've been told it is the end-stops causing it, but I don't know why or how. Here are my current settings:

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