CORS issue even when CORS header are added

const response = await fetch(
        "https://xxxx.xxxxx.workers.dev/api/add/customer",
        {
          method: "POST",
          headers: {
            "Content-Type": "application/json",
          },
          body: JSON.stringify({
        id: xxx,
        cabin: xxxx,
        name: xxxx
      },)
        }
      );

export default {
  async fetch(request, env, ctx) {
    const corsHeaders = {
      'Access-Control-Allow-Origin': '*',
      'Access-Control-Allow-Headers': '*',
      'Access-Control-Allow-Methods': 'GET, POST',
    };
    const { pathname } = new URL(request.url);
    try {
      if (pathname === "/api/view/customers_data") {
        const results = await env.DB.prepare(
          "SELECT * FROM customers_data "
        ).all();
        return new Response(JSON.stringify(results), {
          headers: corsHeaders,
        });
      }else if (pathname === "/api/add/customer") {
        const body = await request.json();
        const results = await env.DB.prepare(
          "INSERT INTO customers_data (cabin, name, email, phone, gender) VALUES(?1, ?2, ?3, ?4, ?5)"
        ).bind(body.cabin, body.name, body.email, body.phone, body.gender).run();
return new Response(JSON.stringify(results), {
          headers: corsHeaders,
        });      }
    } catch (e) {
      return Response.json(e);
    }
   
    });  
  }
};