Não consigo criar uma conta com o nome de usuário que desejo.

Links to Relevant Wiki Articles(s):

• https://en.scratch-wiki.info/wiki/Username

• https://en.scratch-wiki.info/wiki/Censor

There are rules in place on the backend of Scratch to prohibit certain usernames from being created. You might come across these from time to time, and usually the easiest way to get around the rule is to use a different naming convention.