title: Multiple components match node with tagname app-lobby
body: <p><strong>the code was running fine on angular version 8.3.4 but when i updated it to the latest version of angular ( 9 ) i got the following error</strong></p>
  
  <p>following is the stack trace</p>
  
  <pre><code>core.js:3866 ERROR Error: Uncaught (in promise): Error: Multiple components match node with tagname app-lobby
  Error: Multiple components match node with tagname app-lobby
  at throwMultipleComponentError (core.js:5511)
  at findDirectiveDefMatches (core.js:8276)
  at resolveDirectives (core.js:8080)
  at elementStartFirstCreatePass (core.js:14215)
  at ɵɵelementStart (core.js:14249)
  at Module.ɵɵelement (core.js:14324)
  at MainComponent_Template (main.component.html:1)
  at executeTemplate (core.js:7562)
  at renderView (core.js:7387)
  at renderComponent (core.js:8577)
  at resolvePromise (zone.js:836)
  at resolvePromise (zone.js:795)
  at zone.js:897
  at ZoneDelegate.invokeTask (zone.js:431)
  at Object.onInvokeTask (core.js:27769)
  at ZoneDelegate.invokeTask (zone.js:430)
  at Zone.runTask (zone.js:198)
  at drainMicroTaskQueue (zone.js:611)
  at ZoneTask.invokeTask (zone.js:517)
  at ZoneTask.invoke (zone.js:502)
  </code></pre>