Shopify App Proxy is not sending any request using GET method

Technical Q&A
1 
const url = `${getAppProxyBase()}/user-cart`;
      const res = await fetch(url, {
        method: "GET",
      });

But If I am using POST method

image
I can see the request on the server
I am stuck on that…
For example here it works

const url = `${getAppProxyBase()}/auctions/${auctionId}/bid`;

    const res = await fetch(url, {

      method: "POST",

      headers: {

        "Content-Type": "application/json",

        Accept: "application/json",

      },

      body: JSON.stringify({ amount }),

    });

any ideas? I don’t know what to do..

If I am trying await res.text() I receive
Checkout returned non-JSON response text/html

3

If you are using the free version of ngrok that will happen because they are sending a preview html to upgrade to the paid version. on the GET request