The button that closes the iron door is broken. This or that thing breaks often. You need to take good care of it yourself and add some oil when necessary. If it is really broken and cannot be used, it is best to get a new one. You can buy one and replace it yourself, or you can ask someone else to replace it. Use pliers to remove the lock core, make a hole and see if you can see the lock tongue spring. Use a screwdriver to push the lock tongue out and the door will open. The door closing button is broken. First check the power supply, then check whether the button key needs to be replaced, and then check whether the motor of the iron door is normal. Check step by step to see which link is the problem, and then solve it. It is normal for the iron door's closing button to break after being used for a long time.
If you don’t know what’s wrong, you can find a professional door repairman to help you repair it