404 error on Registration API

I want to do registration in my app, I follow yout example user registration

const user = new Backendless.User()
                user.login = this.login
                user.email = this.email
                user.password = this.password

but I got this POST https://api.backendless.com///users/register 404 (Not Found)

It seems that your api does not work at all, since even the generated code does not work for me, which I downloaded from you

Do you have the Backendless.initApp call in your application?

It is documented here: https://backendless.com/docs/js/setup.html