We actually get asked this quite often to use an automatic gate opener for lifting rather than swinging and it is just not possible unless the door being lifted is counter balanced. This is because of the control board of the gate opener. The motor/actuator when being controlled by the gate opener control board will not be allowed to push or pull with significant force and will react to changing forces because of the obstruction sensing built in. All gate openers have obstruction sensing which means when they meet resistance they will stop and reverse for safety purposes. They are all built to be pulling a gate that swings level and with very little amounts of force. The larger motors are just deigned to be able to do heavier duty cycles, not exert more force. They are all regulated through the control board to the exact same levels of force because this is dictated by UL 325 code. The best way to describe this it no manufacturer of a gate opener will allow their opener to knock over and hurt a child. There is no way to distinguish gravity, wind, or any other resistance factor from the resistance of the gate coming in contact with a child. Therefore all gate openers, no matter how strong the motors are, will stop prior to hurting a child and subsequently when there is wind resistance on a gate or gravity resistance on a lifting action it will obstruct. So in this case the fight of the door lifting against gravity would set off the obstruction sensing. This could happen in either direction as well. Lifting of course you are pulling against gravity if the door is not counter balanced. And letting the door down gravity will be pulling it along, which if something pushes on the gate to make it close quicker this could also cause an obstruction. (we see this in swing gates if there is ever a whipping action from a gate moving too fast it will set of the obstruction because of the whipping pull on the gate ahead of the control of the opener)
If you have a multi-meter you can find where if your issue is in the gate opener triggering the gate lock, the gate lock control board, or in the gate lock itself.
A common gate opener technical call we get is in regard to the GSM cellular receiver opening the gate at random times. The reason the gate opens via the cell receiver at random times is because in default, any number that calls the GSM receiver will be able to activate the gate opener. Once you set up your admin phone and white list of authorized gate users you can turn off this function. This will prevent spam calls from opening the gate.