Problem for register user in app mobile

Hello
I am implementing a code to register a user from the application with the api users but I get a fatal error and you tell me if I'm right or wrong
I leave the code:

    registerButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            User user = new User();

            user.setName(nameInput.getText().toString());
            user.setEmail(emailInput.getText().toString());
            user.setPassword(passwordInput.getText().toString());

            final MainApplication application = (MainApplication) getActivity().getApplication();
            final WebService service = application.getService();

            service.createUser(user).enqueue(new WebServiceCallback<User>(getContext()) {
                @Override
                public void onSuccess(Response<User> response) {
                    if (response.isSuccessful()){
                        String message = "Register Successful";
                        Toast.makeText(getContext(), message, Toast.LENGTH_LONG).show();
                    }
                }
            });
@POST("/api/users")
Call<User> createUser(@Body User user);

Regards.

Do you have two user accounts here?

What? Not.

help, I get a bad request when registering

Who is Seba and why you posted exactly the same question at the same time?