Suggestions for what might be the problem?

[Jopar]

Hi! My garage door opener has stopped functioning. The button on the wall control is still sending power, I can hear it trying when the button is pressed, but the door will not open, and the other button to turn the overhead light on the unit on the garage ceiling still works. The door itself is still correctly on the track, as it can be easily manually lifted up and down. In the past the door did have a problem with the chain linkage slipping, but someone looked at that for me, corrected it, and it worked just fine for quite some time. A different person looked at that again for me this time, but doesn't seem to feel the problem is the same this time, but I cannot confirm that to be true at this point.

Is it very likely that the problem is the linkage slipping again, or could there be some other type of issue with the general functioning of a door opener that I should also investigate?

Thank you for any advice!

[TJR]

What brand and model of opener do you have?
So is the chain linkage on the door or the opener?
How and why did the linkage slip in the past?
Do you have a chain drive opener or a screw drive opener?
Chain drive: open the box and look at the gear for wear.
Screw drive: humming shortly and nothing moves, replace the opener.