ERROR: POST http: /php/RelatorioFisico.php net :: ERR_CONTENT_LENGTH_MISMATCH

Someone knows why this error is occurring when I am going to download a spreadsheet ... Being that if I refresh the page the error does not happen again

Controller

$scope.GerarPlanilha = function (){
  $http({
              url: 'http:/php/RelatorioFisico.php',
              method: 'POST',
              responseType: 'arraybuffer',
              headers: {
                  'Content-type': 'application/json',
                  'Accept': 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet'
              }
          }).success(function(data){
              var blob = new Blob([data], {type: "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"});
              saveAs(blob,'ContratosPendentes'+'.xlsx');
          }).error(function(){

          });
      };