Error trying to install "Alert / Toast Notifications" in Angular 6

Using this guide

my html :

<button class="btn btn-default" (click)="showSuccess()">Show Success</button>
<button class="btn btn-danger" (click)="showError()">Show Error</button>

My ts :

import { AfterViewInit, Component, OnInit, ViewContainerRef } from '@angular/core';
import { ToastsManager } from 'ng2-toastr/ng2-toastr';

@Component({
    selector: 'app-categoria',
    templateUrl: '../../views/categoria/index.html',
    styleUrls: ['../../styles/categoria.component.css'],
  providers: [CategoriaService]
})
export class CategoriaIndexComponent implements OnInit{

  constructor(
    public toastr: ToastsManager,
    public vcr: ViewContainerRef
  ){
    this.toastr.setRootViewContainerRef(vcr);
  }

  ngOnInit(): void {}

  showSuccess() {
    this.toastr.success('You are awesome!', 'Success!');
  }

  showError() {
    this.toastr.error('This is not good!', 'Oops!');
  }
}

angular.jon

"styles": [
  "src/styles.scss",
  "node_modules/font-awesome/css/font-awesome.min.css",
  "node_modules/font-awesome/scss/font-awesome.scss",
  "node_modules/angular-bootstrap-md/scss/bootstrap/bootstrap.scss",
  "node_modules/angular-bootstrap-md/scss/mdb-free.scss",
  "node_modules/ng2-toastr/bundles/ng2-toastr.min.css"
],
"scripts": [
  "node_modules/jquery/dist/jquery.js",
  "node_modules/ng2-toastr/bundles/ng2-toastr.min.js"
],

app.module.ts

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';
import { MDBBootstrapModule } from 'angular-bootstrap-md';

import { BrowserAnimationsModule } from '@angular/platform-browser/animations';
import { ToastModule } from 'ng2-toastr/ng2-toastr';


@NgModule({
  declarations: [
    AppComponent,
  ],
  imports: [
    BrowserModule,
    MDBBootstrapModule.forRoot(),
    CommonModule,
    BrowserAnimationsModule,
    ToastModule.forRoot()
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

The application does not load me and sends me this error by console: