Go to the Genie max 1000 site and follow the instructions on how to set up and down limits.

Disconnect the unit from the door by pulling the emergency handle - does the door then move up and down easily? If not, you need to figure out what is mechanically wrong with the door.

While the door is unhooked from the unit - run the opener. does it move all the way up and down throughout the cycle normally?

If so, then it sounds like the force limits as mentioned above need to be reset/adjusted. Just follow the installation protocol for setting both range and force. I think you're supposed to do this annually anyway :)