If its wireless, possibility is someone else has got the same within range.
Got a cat? One of ours worked out how to ring it. Used to go out the back door flap and ring the front door to come back in!!
Yes these wireless door bells have a range of 1-200m so any similar frequency elsewhere can cause it to go off. Also you have to make sure the bell push has the same frequency and set the same as the ringer.
We have had several remote doo bells from reasonably priced to rather expensive. They ing when no one is there or they don't ring when the push is operated. We also had a dog barking for no parent reason.
Think we will get an electric one