Register domain got error "CNPJ / CPFbelongs to another provider"

Domain names/DNS > Transferring domain names to
All .COM.BR registrations require that a legal Brazilian identifier be submitted in the form of a CNPJ (Business Identifier/Cadastro Nacional de Pessoa Juridica ) Or CPF (Individual Tax Number / Cadastro de Pessoa Fisica).

Invalid CNPJ and CPF numbers are typically the largest reason for failed registrations.

If the CPF or CNPJ has already been used for a .COM.BR registration with another Registrar, then the registrant needs to contact the BR Registry to request a change of Registrar prior to registering a new COM.BR domain wth us.

The registry validates the registrant name, company name, and owner contact address associated with the CNPJ/CPF with the federal revenue service of Brazil (Secretariat of the Federal Revenue of Brazil).

When accepting a CNPJ or CPF number please ensure that the submitted values, at minimum,are in the correct format.
CPF Format <11 digits> : NNN.NNN.NNN-NN,
CNPJ Format <14 digits> : NN.NNN.NNN/NNNN-NN).

The following link provides additional information on the CPF including examples of validation scripts: