garage door acting as if there is an obstruction
I have a liftmaster garage door opener which currently is acting erratically. When I try to close it the door will go down a few inches, or else it will go down almost entirely. Then it stops, goes back up, and the light in the opener blinks 7-8 times. If I keep trying to close the door, it will successfully close on the 3rd or 4th try. If this continues I will call someone to fix it, but I am just trying to find out what the problem may be so I am prepared with some information ahead of time.
Thanks for any assistance.