Deployed django application on nginx problems with fetching

I have a django application that deployed on ubuntu 20. It doesn't have certificate yet. When javascript fetches the backend i guess it just throws error

JSON.parse: unexpected character at line 1 column 1 of the JSON data

That's what i get in Chrome, but in Arc Browser everything works fine and without any errors

Here is my code

JS:

const country_icons = document.querySelectorAll(".country-icon");country_icons.forEach((icon)=>{  icon.addEventListener("click", (e)=>{    let id = e.target.id    fetch(`get-country-info/`,{      method: "POST",      body: JSON.stringify({        id : id      }),      headers:{"X-CSRFToken": getCookie('csrftoken') }    })    .then(response => response.json())    .then(data => {      let text = data[e.target.id]      let modal_body = document.querySelector("#modal-body");      modal_body.innerHTML = text      })  })})

views.py

def get_country(request):    data = json.loads(request.body)    country_name = data.get("id")    response_data = {country_name : get_country_info(country_name)}    return JsonResponse(response_data)

everything works if i run the server with python3 manage.py runserver though

I am using Django 5.0.2, DRF 9.14.0, nginx, gunicorn, ubuntu 20