Invalid Usernames/Passwords will not be imported. Usernames need to be a valid e-mail between 4 and 80 characters with no spaces. Passwords need to have a minimum of 4 characters and maximum of 50 characters, we do not allow special character. If you are trying to import multiple items to the same account but are using different passwords for each row in your .csv file the import for the additional items will have problems. You may find it easier to use the Import Settings to upload multiple items to the same account.