title: Ionic 4: 'ion-slide' is not a known element
body: <p>I am using ion-slides in a new component.</p>
  
  <p>carousel.component.html</p>
  
  <pre><code>&lt;ion-slides pager="true" &gt;
    &lt;ion-slide&gt;
      &lt;h1&gt;Slide 1&lt;/h1&gt;
    &lt;/ion-slide&gt;
    &lt;ion-slide&gt;
      &lt;h1&gt;Slide 2&lt;/h1&gt;
    &lt;/ion-slide&gt;
    &lt;ion-slide&gt;
      &lt;h1&gt;Slide 3&lt;/h1&gt;
    &lt;/ion-slide&gt;
  &lt;/ion-slides&gt;
  </code></pre>
  
  <p>carousel.component.ts</p>
  
  <pre><code>import { Component, OnInit } from '@angular/core';
  
  @Component({
    selector: 'app-carousel',
    templateUrl: './carousel.component.html',
    styleUrls: ['./carousel.component.scss']
  })
  export class CarouselComponent implements OnInit {
  
    constructor() { }
  
    ngOnInit() {
    }
  
  }
  </code></pre>
  
  <p>But when I use this component <code>&lt;app-carousel&gt;&lt;/app-carousel&gt;</code> inside my Ionic page, I get the following error:</p>
  
  <pre><code>'ion-slide' is not a known element:
  1. If 'ion-slide' is an Angular component, then verify that it is part of this module.
  2. If 'ion-slide' is a Web Component then add 'CUSTOM_ELEMENTS_SCHEMA' to the '@NgModule.schemas' of this component to suppress this message. ("&lt;ion-slides pager="true" &gt;
    [ERROR -&gt;]&lt;ion-slide&gt;
      &lt;h1&gt;Slide 1&lt;/h1&gt;
    &lt;/ion-slide&gt;
  "): ng:///SharedModule/CarouselComponent.html@1:2
  'ion-slide' is not a known element:
  1. If 'ion-slide' is an Angular component, then verify that it is part of this module.
  2. If 'ion-slide' is a Web Component then add 'CUSTOM_ELEMENTS_SCHEMA' to the '@NgModule.schemas' of this component to suppress this message. ("
      &lt;h1&gt;Slide 1&lt;/h1&gt;
    &lt;/ion-slide&gt;
    [ERROR -&gt;]&lt;ion-slide&gt;
      &lt;h1&gt;Slide 2&lt;/h1&gt;
    &lt;/ion-slide&gt;
  </code></pre>
  
  <p>Please help me to solve this issue.</p>