I am using react and axios. Request header field Access-Control-Allow-Origin is not allowed by Access-Control-Allow-Headers in preflight response

axios. post error.

Request header field Access-Control-Allow-Origin is not allowed by Access-Control-Allow-Headers in preflight response.

I am using the axios, react and redux.

My code is:

  const config = {
    method: 'post',
    url: addActivityUrl,
    data:data,
    headers: {
      'Access-Control-Allow-Origin': '*',
      'Content-Type': 'application/json',
    },
  };

  return function (dispatch) {
    axios.request(config)
        .then(function(response){
          dispatch({type:ADD_ACTIVITY_SUCCESS,payload:response.data});
        } )
        .catch((error)=> {
          dispatch({type:ADD_ACTIVITY_ERROR,payload:error});
        })
  }
}

I set the breakpoint in the error callback function. When I send a post request,the error above will show me.

I looked for the answer on Stack Overflow. I don't found the answer yet.

I don't know the reason.