When deploying on Production with using axios post, I don’t know why domain show twice

I’m trying to communicate with the server through Axios post, but after deploying to Production, I see the uri coming out like this. The client is Netlify and the backend is deployed with AWS Elastic Beanstalk, but I don’t know what’s wrong.
No duplicate environment variables in platforms. It’s unique.

The problem code is this, “yield axios.post(${process.env.REACT_APP_SERVER_URL}/user/register, {})”.

On production, I hope to show “https://api.dino-run.site/user/register” but result is enter image description here
How can i remove domain(dino-run.site)?

Domain url: dino-run.site
Server url: api.dino-run.site

Client code

function* userInfo({ payload }) {
  const { userId, nickName, profileImage } = payload;
  console.log("REACT_APP_SERVER_URL::", process.env.REACT_APP_SERVER_URL);
  try {
    yield axios.post(`${process.env.REACT_APP_SERVER_URL}/user/register`, {
      userId,
      nickName,
      profileImage,
    });
  } catch (err) {
    console.log("user saga Error exist: ", err);
    yield put(userInfoFailure(err));
  }
}

I try to solve it remove REACT_APP_SERVER_URL in Netlify and AWS. Then result shows “https://dino-run.site/undefined/user/register”.
And also remove REACT_APP_CLIENT_URL in Netlify. Then the web site didn’t open.
When I wrote console.log(REACT_APP_SERVER_URL), the result is “api.dino-run.site”.