Does the door opener have a cord that hangs down on it with a plastic hand grip on the end of it?
This cord when pulled down puts the door opener in a disengaged manual mode if someone has pulled on the cord.
The symptoms you are presenting could occur if you have one of these cords on your door opener has somehow had someone pulled on it.
From the user manual of your door opened you need to pull on this cord to release the plastic hand grip from the bracket so it will move up to put the door in engaged mode.
see page 47 of the pdf version of
Have a different door opening but had exact same experience of moving in and someone pulled on the cord and then I had to look up the user manual to figure how to put it back in engaged mode.