I have a Genie Excelerator garage door opener.
When I press on either the main garage or car remote the door opens about 5 inches the stops. If I'm in the garage I have to press the button until the door fully opens. For the remote. I have to get out of my vehicle, press the remote "open" button while lifting the garage door handle using my hand.
Both internal garage censors are 5" above the floor also.
What is going on here?
What should I troubleshoot on?

Do you have a Lock/Unlock button?
Make sure that you have not electronically locked the opener.

This would be my first step to troubleshoot the problem.

Fixing the Sensor on Overhead Garage Doors | Home Guides | SF Gate

Let me know if it works or not.