error validations reactive form not display on my PC only ?

problem

meaning when user name is empty error not display but on another pc

same component work without change any thing

I work on angular 7 project

I work on reacive form all controls validation empty not work on my pc

i take ts and html component and put them in another project on nother pc

it working without change any thing

so how to solve the problem and why this error display ?

my form as below

"error" class="alert alert-danger">{{error}}

Reset Password

"ChangePasswordForm" (ngSubmit)="onSubmit()">

Reset Password

class="form-group">

UserName

"text" formControlName="userName" [(ngModel)]="userservice.formData.userName" class="textboxclass" [ngClass]="{ 'is-invalid': submitted && c.userName.errors }" />

"submitted && c.userName.errors" class="invalid-feedback">

"c.userName.errors.required">UserName is required

"c.userName.errors.minlength">UserName must be at least 6 characters