尽管来自服务器的HTTP 200响应，但Angular App中的HttpErrorResponse

Question

我使用Flask在Python中编写了一个简单的API。我还使用stackblitz.com在Angular中编写了一个简单的应用程序。当我尝试从服务器获取数据时，服务器返回HTTP 200响应，但控制台为loggin HttpErrorResponse，其中包含以下信息： 错误：ProgressEvent 标头：HttpHeaders 消息：“ http://127.0.0.1:5000/test的Http故障响应：0未知错误” 名称：“ HttpErrorResponse” 好的：错误 状态：0 statusText：“未知错误” 网址：“ http://127.0.0.1:5000/test” 原始：HttpErrorResponse

我已经在Postman中测试了API，并且可以正常工作。

API

    from flask import Flask, jsonify, request
    app = Flask(__name__)

    @app.route('/test')
    def test():

        return jsonify(
                { 
                "protoid": 1,
                "operator": "Example",
                }
        )

    app.run()

app.module.ts

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { FormsModule } from '@angular/forms';
import { HttpClientModule } from '@angular/common/http';

import { AppComponent } from './app.component';
import { HelloComponent } from './hello.component';
import { GetterService } from './getter.service';
import { TestComponent } from './test/test.component';

@NgModule({
  imports:      [ BrowserModule, FormsModule, HttpClientModule ],
  declarations: [ AppComponent, HelloComponent, TestComponent ],
  bootstrap:    [ AppComponent ],
  providers: [GetterService]
})
export class AppModule { }

getter.service.ts

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { Observable } from 'rxjs'

@Injectable()
export class GetterService {

  constructor(private http: HttpClient) { }

  _url = 'http://127.0.0.1:5000/test'

  getObject(): Observable <Object> {
    return this.http.get(this._url)
  }

}

test.component.ts

import { Component, OnInit } from '@angular/core';
import { GetterService } from '../getter.service';

@Component({
  selector: 'app-test',
  templateUrl: './test.component.html',
  styleUrls: ['./test.component.css']
})
export class TestComponent implements OnInit {

  constructor(private getter: GetterService) { }

  ngOnInit() {
  }

  object: Object;

  getObject() {
    return this.getter.getObject()
               .subscribe(data => this.object = data)
  }

}

我想将JSON对象保存到对象变量中，但是我正在获取HttpErrorResponse