app.module.ts

import {BrowserModule} from '@angular/platform-browser';
import {BrowserAnimationsModule} from '@angular/platform-browser/animations';
import {NgModule} from '@angular/core';
import {CommonModule} from '@angular/common';
import { MatGridListModule, MatToolbarModule } from '@angular/material';  // <----- HERE
import {AppComponent} from './app.component';

@NgModule({
  imports: [
    BrowserModule,
    CommonModule,
    MatToolbarModule,
    MatGridListModule,      // <----- HERE
    BrowserAnimationsModule
  ],
  declarations: [AppComponent],
  bootstrap: [AppComponent],
  providers: []
})
export class AppModule {}