Validation using react hook form results in an error

import React, { useEffect } from 'react';
import { useForm } from 'react-hook-form';

const login = () => {

    const {register, handleSubmit} = useForm();

    return (
        <div>
            <div className="min-h-screen bg-gray-50 flex flex-col justify-center py-12 sm:px-6 lg:px-8 bg-gradient-to-r from-gray-700 via-gray-800 to-gray-900">
            <div className="sm:mx-auto sm:w-full sm:max-w-md">
                <h2 className="mt-6 text-center text-3xl font-extrabold text-white">
                Sign in to your account
                </h2>
                <p className="mt-2 text-center text-sm text-gray-600 max-w">
                Or &nbsp;
                <a href="/register" className="font-medium text-indigo-600 hover:text-indigo-500">
                    Register for an account
                </a>
                </p>
            </div>
            <div className="mt-8 sm:mx-auto sm:w-full sm:max-w-md">
                <div className="bg-white py-8 px-4 shadow sm:rounded-lg sm:px-10">
                    {/* Form */}
                <form className="space-y-6" action="/login" method="POST" onSubmit={handleSubmit((data)=>{
                    alert(JSON.stringify(data))
                })}>
                    <div>
                    <label htmlFor="email" className="block text-sm font-medium text-gray-700">
                        Email address
                    </label>
                    <div className="mt-1">
                        <input ref={register} id="email" name="email" type="email" autoComplete="email" required className="appearance-none block w-full px-3 py-2 border border-gray-300 rounded-md shadow-sm placeholder-gray-400 focus:outline-none focus:ring-indigo-500 focus:border-indigo-500 sm:text-sm" />
                    </div>
                    </div>
                    <div>
                    <label htmlFor="password" className="block text-sm font-medium text-gray-700">
                        Password
                    </label>
                    <div className="mt-1">
                        <input ref={register} id="password" name="password" type="password" autoComplete="current-password" required className="appearance-none block w-full px-3 py-2 border border-gray-300 rounded-md shadow-sm placeholder-gray-400 focus:outline-none focus:ring-indigo-500 focus:border-indigo-500 sm:text-sm" />
                    </div>
                    </div>
                    <div className="flex items-center justify-between">
                    <div className="flex items-center">
                        <input ref={register} id="remember_me" name="remember_me" type="checkbox" className="h-4 w-4 text-indigo-600 focus:ring-indigo-500 border-gray-300 rounded" />
                        <label htmlFor="remember_me" className="ml-2 block text-sm text-gray-900">
                        Remember me
                        </label>
                    </div>
                    <div className="text-sm">
                        <a href="#" className="font-medium text-indigo-600 hover:text-indigo-500">
                        Forgot your password?
                        </a>
                    </div>
                    </div>
                    <div>
                    <button type="submit" className="w-full flex justify-center py-2 px-4 border border-transparent rounded-md shadow-sm text-sm font-medium text-white bg-indigo-600 hover:bg-indigo-700 focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-indigo-500">
                        Sign in
                    </button>
                    </div>
                </form>
                <div className="mt-6">
                    <div className="relative">
                    <div className="absolute inset-0 flex items-center">
                        <div className="w-full border-t border-gray-300" />
                    </div>
                    <div className="relative flex justify-center text-sm">
                        <span className="px-2 bg-white text-gray-500">
                        Or continue with
                        </span>
                    </div>
                    </div>
                    <div className="mt-6 grid grid-cols-2 gap-3">
                    <div>
                        <a href="#" className="w-full inline-flex justify-center py-2 px-4 border border-gray-300 rounded-md shadow-sm bg-white text-sm font-medium text-gray-500 hover:bg-gray-50">
                        <span className="sr-only">Sign in with Google</span>
                            <img className="g-tile" src="/google-tile.png" />
                        </a>
                    </div>

                    </div>
                </div>
                </div>
            </div>
        </div>    
</div>
    )
}