ng2 fileupload is not working in angular7?

Question

I have an angular8 app in which i want to send file on server.I am using ng2-file-upload.

Here is my component.ts

import { FileUploader, FileLikeObject } from 'ng2-file-upload';

const URL = `${environment.api_base_url}/files`; 

public uploader: FileUploader = new FileUploader({
  url: URL,
  disableMultipart : false,
  autoUpload: true,
  method: 'post',
  itemAlias: 'file',
  allowedFileType: ['pdf', 'csv']
});

public onFileSelected(event: EventEmitter<File[]>) {
  const file: File = event[0];
  console.log(file);
} 

In component.html i have this

<button class="btn btn-primary btn-submit btn-block mb-1" (click)="fileInput.click()">Upload Customer CSV</button>
<input type="file"  class="d-none"  id="csvFileUpload" #fileInput ng2FileSelect [uploader]="uploader" (onFileSelected)="onFileSelected($event)">

Now http post request it is not sending in network tab when i select any file. It only prints console that is in onFileSelected function. It prints file object.

What am i doing wrong?