最初由 DayInDayOUt 发布
There are so many reasons. I'll give you a few.
1. pulled the manual handle accidentally (not in your case but maybe for others)
2. lifting force(torque) is too weak
3. broken gate lift coil
4. stuck rail
5. got jammed at one end
6. locked garage door ;-)
For qiuhc12's suggestion: safety sensor? no. too tight chain? maybe.
Leave me your phone number and I will give you call if you like.