Punchout Test Connection gives error 204 (POR-2010665)

I am getting this error while trying to Test Connection on punchout catalog

A server side error occurred while connecting to the punchout site. The error code is 204. (POR-2010665)

here is my setup

and this is the log

The PunchOutSetupResponse cXML I am returning to Oracle looks like this:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?><!DOCTYPE cXML SYSTEM "http://xml.cxml.org/schemas/cXML/1.1.007/cXML.dtd"><cXML payloadID="20250222043801.SessionId.78052@fa-eqwf-test-saasfaprod1.fa.ocs.oraclecloud.com" timestamp="2025-02-22T16:38:01.641Z">

<Response>

<Status code="200" text="success"/>

<PunchOutSetupResponse>

<StartPage>

<URL>//my_redirection_url</URL>

</StartPage>

</PunchOutSetupResponse>

</Response>

</cXML>