I received a registration message for no reason.

Uh-huh, you notice that someone is using your mobile phone number to register a website account or a game account! But it is useless for this person to do so, because if you don't reply or he can't see the verification code, his account registration will be unsuccessful! I suspect that someone is joking with you or playing with you. Think about who likes to annoy you or who has offended who recently! Don't reply to those numbers you don't know! Don't disclose your mobile phone number online! Don't worry!