Little bluebird registration shows a cross.

What you want to ask is why Little Bluebird registered to show the cross? The reason is that the user name already exists and the password does not meet the requirements.

1. User name already exists: if the selected user name has been registered and used by others, a cross will be displayed.

2. The password does not meet the requirements: the system has some requirements, such as the length of the password, including special characters, etc.