I have a lift master elite 8550 garage door opener. The remote no longer operates the garage door and all 3 lights light up when I push any button on the remote.

SOURCE: remotes don't work (3)

Did you inadvertantly hit the "vacation lock" button on the Mounted push button? This will cause the remotes not to work. Try hitting the button again, and then see if the blinking goes to solid green.

Good Luck

SOURCE: Lift-Master garage door opener Model 1045-6 1/3 hp

There is a thermal cut out in the motor, usually the motor must cool before the opener will operate again. If the opener only operates 3 times it must be heating up too quickly.
First you opener is only made to do your job for you, which is opening and closing the door. If the door does not operate properly manually the opener will not operate properly.
When the door is disconnected from the opener it should lift easilly, it should basically stay at whatever point you let go of it (midway and fully open) and it should close without slamming down. It does not matter what size the door is!!! If it does not something is wrong with your springs and the door can be VERY DANGEROUS!!
With that being said it sounds more like a static lock-up possibly a loose ground or even a circuit problem in the home.
Bryan

SOURCE: i have a pmx300IC genie

palm treo 700w off no open

SOURCE: Garage door does not function makes couple of buzzing sounds only

Remove the cover and check out the drive gear. It is white nylon and is probably stripped.

SOURCE: Craftsman Model 139.53684 Security+ Keyless Entry

To answer your question the opener is in vacation mode. Press and hold for 3 seconds the button on your wall control with the lock icon. The green light will stop flashing and you will be back in business.