Can I only log in with a verification code?

Only. Lian Xin can only use the mobile phone verification code to log in, because Lian Xin's registration must use the mobile phone number, that is, the account number, so Lian Xin's login must also use the account number, that is, use the mobile phone number to log in to Lian Xin. Register with your mobile phone number and use it after verifying the SMS verification code. You can't unbind the mobile phone number.