'mat-step' is not a known element: 1. If 'mat-step' is an Angular component, then verify that it is part of this module. code example

Example: 'mat-form-field' is not a known element:

@NgModule({
  imports: [
    MatButtonModule,
    MatFormFieldModule,
    MatInputModule,
    MatRippleModule,
 ]
 ....