Нет ни одного заголовка. Пост запрос. Тело идентичное
const body = {
        email: "ded@yandex.ru",
        phone: "12312300049",
        fullName: "qweqwrqwe",
        password: "111111",
        username: "v1097144",
        birthday: "1123"
      }
axios({
        method: 'post',
        url: baseURL + '/api/users',
        data: body
      })
.then(res => console.log(res))
Access to XMLHttpRequest at '
example.com/api/users' from origin '
localhost:3000' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: The 'Access-Control-Allow-Origin' header contains multiple values '
localhost:3000, *', but only one is allowed.