One cortex motor port not working

Does anyone have any bright ideas why a Cortex motor port might suddenly stop working with no visible signs of damage? I have tried multiple motors and motor controllers, and they work in all the ports except port 3. I would rather not be down a cortex so any ideas that might help me get it fixed would be awesome.

you might have used one bad motor controller on it and it could of blown that port. My “B” team has had the same problem so what I told them to do was try to Y some of the cables