You may get an ERROR CODE 15 on your Chamberlain LiftMaster garage door opener. If that’s the case you will need to change the motor with travel module. Follow along in this how-to video to see if this is something you can tackle on your own.
If your Chamberlain LiftMaster is under warranty give them all call at 1-800-528-5880. Have the model number and serial number ready for tech support. This is how they determine if your unit is under warranty.