which condition can we add to check if user is already registered or not in react js and mysql?

import axios from 'axios';
import { useState } from 'react';
import { useNavigate } from 'react-router-dom';

function Register() {
    const nevigate = useNavigate();

    const AddUser = () => {
        axios.post('http://localhost:3001/create', { name: name, email: email, contact: contact }).then((response) => {
            console.log(response);
        })
    }

    const getUser = async () => {
        const response = await axios.get('http://localhost:3001/users')
        console.log(response.data);
    }

    console.log(getUser());

    const [name, setName] = useState("");
    const [email, setEmail] = useState("");
    const [contact, setContact] = useState();

    return (
        <div classNameName="App">
            <section className="vh-100 bg-image"
                style={{ backgroundImage: "url('https://mdbcdn.b-cdn.net/img/Photos/new-templates/search-box/img4.webp')" }}>
                <div className="mask d-flex align-items-center h-100 gradient-custom-3">
                    <div className="container h-100">
                        <div className="row d-flex justify-content-center align-items-center h-100">
                            <div className="col-12 col-md-9 col-lg-7 col-xl-6">
                                <div className="card" style={{ borderRadius: "15px", overflow: 'hidden' }}>
                                    <div className="card-body p-5">
                                        <h2 className="text-uppercase text-center mb-5">Register Yourself</h2>

                                        <form onSubmit={AddUser}>

                                            <div className="form-outline mb-4">
                                                <label className="form-label" for="form3Example1cg">Your Name</label>
                                                <input type="text" id="form3Example1cg" className="form-control form-control-lg"
                                                    onChange={event => {
                                                        setName(event.target.value);
                                                    }} />
                                            </div>

                                            <div className="form-outline mb-4">
                                                <label className="form-label" for="form3Example3cg">Your Email</label>
                                                <input type="email" id="form3Example3cg" className="form-control form-control-lg"
                                                    onChange={event => {
                                                        setEmail(event.target.value);
                                                    }}
                                                />
                                            </div>

                                            <div className="form-outline mb-4">
                                                <label className="form-label" for="form3Example3cg">Your contact number</label>
                                                <input type="number" id="form3Example3cg" className="form-control form-control-lg"
                                                    onChange={event => {
                                                        setContact(event.target.value);
                                                    }}
                                                />
                                            </div>

                                            <div className="d-flex justify-content-center">
                                                <button type="button"
                                                    className="btn btn-success btn-block btn-lg gradient-custom-4 text-body" onClick={() => nevigate('/ImgCards')}>Register</button>
                                            </div>
                                        </form>

                                    </div>
                                </div>
                            </div>
                        </div>
                    </div>
                </div>
            </section>
        </div>
    );
}

export default Register;

This is registration form and i am using this form when user clicks on image. after registering when user clicks on image after redirecting on page it is again asking for the registration.

How can I solve this error?