Yes, as long as the person at the door has the right to enter and can prove it. Saying you know the owner is not enough: we check before we open, and we explain how when you call.
On the coast this happens a lot. Many homes in Torrevieja and the Vega Baja are holiday homes and the owner lives elsewhere for much of the year. The person who finds the door locked may be a relative, whoever looks after the house or whoever runs a holiday let.
If you are the owner and you are far away, the best thing is to message us yourself on WhatsApp, in your own language, and tell us who will be there. That way everything is clear before we go. More on this in door opening.