So i'm a student in computer science , i'm kinda newbie , i ran into a problem that i couldn't solve , so i want to fetch from my bdd mongo every x seconds , and show the result in the html. i have a function called getItems that does that for me , it works perfectly , hence when i try to set call it with setIntervel it works ! but only for 30 or 40 seconds and then breaks. this is my code :

setInterval(getItems , 1000 ) ; 


const getItems = async () => {
  const requestOptions = {
    method :'GET',
  };
  const response = await fetch('/user/listed', requestOptions);
  const response2 = await fetch('/user/me', requestOptions);
  items = await response.json(); 
  owned = await response2.json() ; 
   
  if (response.ok && response2.ok) {
    // delete all the old values in listed 
   var e =document.getElementById("listed") ; 
   var child = e.lastElementChild ; 
   while (child){
     e.removeChild(child) ; 
     child = e.lastElementChild ; 
   }
   // delete all the old values in boughts 
   var e2 =document.getElementById("bought") ; 
   var child2 = e2.lastElementChild ; 
   while (child2){
     e2.removeChild(child2) ; 
     child2 = e2.lastElementChild ; 
   }
    // adding new values 
    for (var key in items ){
     
      
      const node = document.createElement("li");
      const textnode = document.createTextNode(items[key].name + " : " + items[key].price);
      node.appendChild(textnode);
      node.setAttribute("id", items[key]._id)  ; 
      const buy = document.createElement("button") ; 
      const buytext = document.createTextNode("buy") ; 
      buy.setAttribute("id", items[key]._id) ; 
      buy.setAttribute("onClick" , "buy(this.id)")
      buy.appendChild(buytext) ; 
      node.appendChild(buy) ; 
      document.getElementById("listed").appendChild(node);


    }
    // adding new values 
    for (var o in owned.bought){
      
      const node = document.createElement("li");
      const textnode = document.createTextNode(owned.bought[o].name + " : " + owned.bought[o].price);
      node.appendChild(textnode);
      node.setAttribute("id", [o]._id)  ; 
      document.getElementById("bought").appendChild(node);
  }

  }
}

and here is a picture of the error :

Thank you in advance !

here is my backend , the user/listed and user/me routes actually are :

module.exports.me =
  async (req, res) =>  {
    const user = await User.findById(req.userId);
    console.log(user);
    console.log(req.userId);
    res.status(200).json(user);
  }

  module.exports.listed =
  async (req, res) =>  {
    const listed = await Listed.find();
    console.log(listed);
    res.status(200).json(listed);
  }