I've been having intermittent problems with my garage door opener either reopening after closing (fully) or opening after partial closing. I could force it closed by holding down the button. This only happened occasionally. The indicator lights had the "up" light flash four times then then "down" once, and the suggestion seemed to be to reset the travel. When I tried to do this, the garage door stops very quickly on the "down" setting and now everything is now 100 times worse --- the door won't go down more than a foot and then stops, since the new "bottomed out" setting is completely wrong. Attempts to do it again get stuck in exactly the same place.
Please refer to above image.
The "top" adjustment is for the UP (open) travel limit switch for the door... To lengthen the up travel, ( more "up" ) turn the slotted screw adjustment to the right. To shorten the up travel, turn the slotted screw adjustment the left.
The "bottom" adjustment is for the DOWN (close) travel limit switch for the door... To lengthen the down travel, ( more "down" ) turn the slotted screw adjustment to the left. To shorten the down travel, turn the slotted screw adjustment to the right.
Hope this helps you, 👍