Using laravel api how to show the validation error in vue js?

my store api controller method

 public function register(Request $request)
    {
        $attributes = $request->validate([
            'name' => 'required',
            'email' => 'required|unique:users,email',
            'password' => 'required|confirmed',
        ]);

        $user = User::create($attributes);


        return response()->json([
            'username' => $user->name
        ]);
    }

my store

import { defineStore } from 'pinia'

export const useAuthStore = defineStore('auth', {
  state: () => ({
    user: '',
    token: '',
  }),
  actions: {
    async registerUser(formData) {
      try {
        const res = await fetch('http://127.0.0.1:8000/api', {
          method: 'POST',
          headers: {
            'Content-Type': 'application/json',
          },
          body: JSON.stringify(formData),
        })
        if (!res.ok) {
          console.log('Error occured')
        } else {
          const data = await res.json()
          console.log(data)
        }
      } catch (error) {
        console.log(`Error during registration ${error}`)
      }
    },
  },
  getters: {},
})

my register method

and getting this CORS error in network tab not any preview or anything.

how to get those validaton error ?