csv file being downloaded with null content - Angular 9

Question

I have a code that makes a request my api in Node that returns me a csv file, but when I download the file, it comes only with null content

generateReport() {
this.layoutService.loading(this.buttons.report, true);
this.reportService.generateReport(this.purchases).subscribe(
  (file) => {
    this.layoutService.loading(this.buttons.report, false);
    var newBlob = new Blob([file], { type: "text/csv" });
    console.log(file)
    const data = window.URL.createObjectURL(newBlob);

    var link = document.createElement('a');
    link.href = data;
    link.download = "relatório-adimplência.csv";
    link.dispatchEvent(new MouseEvent('click', { bubbles: true, cancelable: true, view: window }));
  },
  (err) => {
    this.layoutService.loading(this.buttons.report, false);
    console.log(err)
    this.layoutService.error(err.error)
  }
 )                                                                                                    
}