Responding with Another Website: WordPress

Referencing this guy:

I have the following setup.

For debugging purposes, send ALL traffic to the handler.

addEventListener('fetch', event => {    

We then send that event to the following function and do some pretty standard stuff.

async function sendToPantheon(event) {
    var public_endpoint = '';
    var pantheon_endpoint = '';
    var isExpected = event.request.url.toString().includes(public_endpoint);

    // We don't want to break requests we were not expecting.
    if (!isExpected) {

    var modified_request = event
        .replace(public_endpoint, pantheon_endpoint);

    var headers = new Headers();

    // Get the original payload, including headers, contents and so on.
    var new_response = await fetch(modified_request);

    var headers = new Headers();
    for (var kv of new_response.headers.entries()) {
        headers.append(kv[0], kv[1]);

    return new Response(
            status: new_response.status,
            statusText: new_response.statusText,
            headers: headers

My issue is, hitting /blog is working 100% fine as far as I can see. Additionally, hitting permalinks such as /blog/my-test-post is working 100% fine.

But when I try to hit the administration area /blog/wp-admin I am getting a 404.

Example CURL:

HTTP/2 404
date: Fri, 11 Jun 2021 15:23:10 GMT
content-type: #<Mime::NullType:0x00007f300506a630>; charset=utf-8
cf-ray: 65dbd6ccdd97180f-ATL
cache-control: no-cache
set-cookie: ahoy_visitor=f5c3a9a2-692a-4af4-904e-67289c628fb9; path=/; expires=Sun, 11 Jun 2023 15:23:10 GMT; secure, ahoy_visit=5c599dfc-ce26-42b1-b908-a182c8e9fa9d; path=/; expires=Fri, 11 Jun 2021 19:23:10 GMT; secure
strict-transport-security: max-age=31536000; includeSubDomains
vary: Accept-Encoding
via: 1.1 vegur
cf-cache-status: DYNAMIC
cf-request-id: 0a9d4494080000180ff502b000000001
expect-ct: max-age=604800, report-uri=""
referrer-policy: strict-origin-when-cross-origin
x-content-type-options: nosniff
x-download-options: noopen
x-frame-options: SAMEORIGIN
x-permitted-cross-domain-policies: none
x-request-id: 9b6f413a-dcab-4757-8271-a66e714a8966
x-runtime: 0.013544
x-xss-protection: 1; mode=block
report-to: {"endpoints":[{"url":"https:\/\/\/report\/v2?s=tVMkwhIq2OdSBqN%2FSgskgCFkUVjSlExmwPlk2kJ7QQ7tt6Z8HEGyKJetyaFLBYQkCZARYTXYVTdtffJ1r5s6G9d7g1WITUr5tP173aizpTBj9Ls6IIwxEsQ%2F6ZL50d9Ro%2Fd5"}],"group":"cf-nel","max_age":604800}
nel: {"report_to":"cf-nel","max_age":604800}
server: cloudflare

I see that the content-type looks a little weird… but that doesn’t explain the 404.

The end goal of course is to be able to access the area via, passing cookies and so forth.

I’ve spent some time googling, working with the host support team and so on, but figured I’d ask the Cloudflare community.

Where can I go from here?