To access the Blue Zone you must be accredited. For holders of Brazilian passports, this accreditation is carried out by the Ministry of Foreign Affairs until November 15, 2023.
Information about accreditation in the Blue Zone is available through the Press Release made by the Ministry of Foreign Affairs, available at the link:
https://www.gov.br/mre/pt-br/canais_atendimento/imprensa/notas-a-imprensa/cop28-2013-credenciamento