How to set password (or auth) to the Samsung washer smart control?

OK so we have just bought a new Samsung Washer and we set it up for Smart Things app and it work very well. But then, another user (not in the same virtual home in smart things app) came and hold on the AP button for 3 second and they can set themself to become the owner of the machine and throw me away. But then I do the same thing and throw them away too. And my question is: how can I set the password (or some auth) to the washing machine’s smart things feature so anyone else (except for the members I added to the smartthings app) cannot add themself to the machine by just clicking AP button? Thanks for any help!