Why my user cannot to be register during registration showing this error not permitted to register

sorry the title was wrong this should be user cannot to register not regarding login

This means the user has been caught by a filter such as the ban filter or (more likely) the spam service. If you are testing over and over yourself, then you would get that eventually as the service will think you are spam. If the user who is trying to register is known to be a valid user, you can white list if needed. Please see the following guide on this