I've been using back4app for a challenge someone has give me. I use vanilla javascript with this and I need help with this error. It's error 206 Insufficient Auth. Here's my code. It's supposed to update the users className.

function updateClassName(foundUser) {
    const updateTo = document.getElementById("s-className").value;
    foundUser.set('classname', updateTo);
    foundUser.save().then(function(user) {
      console.log(user.get("classname"));
    }).catch(function(error) {
      console.log(error.code + " " + error.message);
    });
  }
  
  function read() {
    const User = Parse.Object.extend('User');
    
    const query = new Parse.Query(User);
    
    query.equalTo("classname", 'undefined');
    query.first().then(function(user) {
      if(user) {
        console.log(user.get("username"));
        updateClassName(user);
      }
      else {
        console.log("Nothing found...");
      }
    })
    
  }