在 Angular 9 中使用 hhtp 发布请求

我是 Angular 的新手，并尝试在 Angular 9 中使用 Web API。我的 http get 请求运行良好，但是当我发送 hhtp post 请求时，我发现以下错误 zone-evergreen.js:2845 POST http://127.0.0.1:8000 /insert 500（内部服务器错误）core.js:6189 错误在发布请求中，我创建了一个创建用户组件和一个服务。我创建的 Web API 在 LARAVEL 中。我使用 POSTMAN 工具提交 GET/PUT/POST/DELETE，这些请求运行良好，但在 angular get 请求中有效，而 post 请求无效。我找不到以下错误的原因。请帮助我解决这个问题。我将非常感谢。我的不同文件的代码如下

**user.service.ts**

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


@Injectable({
  providedIn: 'root'
})
export class UserService {

  constructor(private http: HttpClient) { }

  getUser(): Observable<any> {
    return this.http.get('http://127.0.0.1:8000/basic');
  }
  addUser(form: any): Observable<any> {

    return this.http.post('http://127.0.0.1:8000/insert', form);
  }
}

create-user.component.html
<br><br>
<form #form="ngForm" (submit)="onSubmit(form)">
  <div class="form-group">
    <label for="name">Name</label>
    <input type="text" class="form-control" name="name" ngModel placeholder="Enter Name">
    <small id="emailHelp" class="form-text text-muted"></small>
  </div>
  <div class="form-group">
    <label for="email">Email address</label>
    <input type="email" class="form-control" name="email" mgModel aria-describedby="emailHelp"
      placeholder="Enter email">
    <small id="emailHelp" class="form-text text-muted"></small>
  </div>
  <div class="form-group">
    <label for="password">Password</label>
    <input type="password" class="form-control" name="password" ngModel placeholder="Password">
  </div>

  <button type="submit" class="btn btn-primary">Submit</button>
</form>
create-user.component.ts
import { Component, OnInit } from '@angular/core';
import { NgForm } from '@angular/forms';
import { UserService } from '../services/user.service';

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

  constructor(private service: UserService) { }

  ngOnInit(): void {
  }

  onSubmit(form: NgForm) {
    this.service.addUser(form.value).subscribe(
      res => {
        alert('data has been added');
      }
    )
    console.log(form.value);
  }

}