Response with status: 0 for URL: null

Dear I have the following error, I want to return an error message with the content inside a bootstrap alert, but it does not leave me as you see in the images. What do you think it could be, thanks in advance. I'm working with Node.js, Angular, Express and MongoDB.

error => {
    var errorMessage = <any>error;

    if(errorMessage != null){
      this.errorMessage  = error;
      console.log(error);