Coupler Mode Not Working

I was trying to attach trailers and its not working
I looked up the keybind bc I couldnt remember (I thought it was L but wasn't sure) it and saw it was L I tried that and it didn't work so I thought I must've changed it. I spent the next 30 minutes looking through controls trying to find it, I found what I thought might be it but it was L so if it was then it would work right but it didn't so I followed the advice of antother forum and reset everysingle one of my bindings (which is gonna be a hiuge pain to fix now) and it still didn't work so somethings wrong.

I changed from a modded to default map in case that was the problem, I thought it might be just a UI problem where the glowing bubble wasn't showiung up but it dosen't connect so I have no idea.

Anyone know if theres a fix/ possible ideas?

 

What specific vehicles are you using?

 

all of them, the ute/pickup truck the semi truck none are working