garage door won't close sometimes

This is a followup to the thread here, since problem resurfaced: garage door usually won't close – even trolley without door won't move much

Hopefully with better details and some attached pictures.

My garage door will not shut all the way. The trolley will move partway down the track (sometimes only a little all the way up to halfway or more), but at some point, it will stop, and re-open by itself, and the lights will flash 10 times.

The opener: Lift Master Forumla I Whisper Drive, 1/2 HP
model 1280LM

When I try to close the garage, the lights on the sensors do not go out (solid green the whole day).

Also, if I detach the door and just run the trolley, I get the same behavior.

Based on advice on the previous thread, I opened it up and looked at all the wiring, gear, belt — nothing I could immediately see that was wrong (but pics attached).

I did notice, on the bottom side of the trolley (pic below), there is a metal plate that sits between the trolley and the track, and has two teeth that hook it on to the trolley (through the bottom) on either end. You’ll notice the picture below only has teeth on one side. I compared to my other openers, and they both have teeth on both sides (4 teeth in all), The end of the metal sheet without the teeth can pivot fairly freely to either side. (I tried rolling up some duct tape and jamming it in there to keep it from moving, but that didn’t seem to help.)

I’ve tried tightening bolts everywhere (where the opener attaches to the roof), and I tried tightening and loosening the belt), but none of that seemed to help.

The sensors near the floor do not seem to move at all when the garage is moving, and they are mounted directly to the wall.

Appreciate any help in fixing this.