Multiple components match node with tagname app-lobby

Question

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

following is t

Answer 1

Probably you have more than one component with the same selector tag name app-lobby

...
@Component({
   selector: 'app-lobby',
...

Please double check to ensure that only one component selector tag name is app-lobby.