Element Statement 'env:Envelope' Not found XML SOAP

Question

I am trying to consume a WS from the GNRE Mill, but in a UF query it returns the following validation error: Cannot find the declaration of element 'env:Envelope'

Follows the XML:

    <env:Envelope xmlns:env="http://www.w3.org/2003/05/soap-envelope">  
     <env:Header>
      <gnreCabecMsg xmlns="http://www.gnre.pe.gov.br/wsdl/GnreConfigUF">
       <versaoDados>1.00</versaoDados>
      </gnreCabecMsg>
     </env:Header>  
    <env:Body>
     <gnreDadosMsg xmlns="http://www.gnre.pe.gov.br/wsdl/GnreConfigUF">
      <TConsultaConfigUf xmlns="http://www.gnre.pe.gov.br">
       <ambiente>2</ambiente>
       <uf>RS</uf>
       <receita>100099</receita>
      </TConsultaConfigUf>
     </gnreDadosMsg>
    </env:Body>  
   </env:Envelope>