Click on Forgot Password on the login screen and enter the ID (e-mail) you registered when registering as a member. A link to set a new password will be sent to that email.
Click Reset password on the instructions to complete the change to a new password, and then visit the app again to log in.
The e-mail sent when you change your password has an expiration date, so if you do not check it within the time limit, it may be displayed as an expired page.
If the email is not verified, please check the spam folder again.