Data is not getting captured in mongodb - node.js

Question

Data is not getting captured in mongodb . For frontend I am using angular and at backend I am using node js. I tested the backend api using postman , data is getting captured in mongoDb , where as when I am submitting from an angular form data is not getting captured.
//UI logic
<div class="row mt-5">
<div class="col-md-6 mx-auto">
<div class="card">
<div class="card-header">
<h3>Register</h3>
</div>
<div class="card-body">
<form>
<div class="form-group">
<label>Email:</label>
<input type="text" class="form-control" name="email" [(ngModel)]="registerUserData.email" email required>
</div>
<div class="form-group">
<label>Password:</label>
<input type="password" class="form-control" name="password" [(ngModel)]="registerUserData.password" required>
</div>
<button (click)="registerUser()" class="btn btn-info float-right">Register</button>
</form>
</div>
</div>
</div>
</div>
//service
private urlR="http://localhost:3000/register";
private urlL="http://localhost:3000/login";
constructor(private httpClient:HttpClient) { }
registerUser(abc){
return this.httpClient.post<any>(this.urlR,abc);
}
//submit method
registerUser() {
this.authService.registerUser(this.registerUserData)
.subscribe(
res=> console.log(res),
err=> console.log(err)
)
}
//backend node
app.post('/register' , (req,res) => {
const newUser = new Expo({
email:req.body.email,
password:req.body.password
});
newUser.save( (err , registeredUser) => {
if(err) {
console.log(err);
} else {
res.status(200).send(registeredUser);
}
});
});