APEX

Hello.

I am calling an external REST API from my APEX app. After performing a call to the API through a Dynamic Action in Page 1, it is supposed to give a response to Page 1 containing an external link which then gets triggered using JavaScript. After completing the form on the external link, the API is supposed to redirect to Page 2, which was mentioned in the initial request as the ReturnPath. However, APEX pages are not equipped to deal with POST responses. I then created an ORDS handler, as shown below.

I also wrote the following PL/SQL code in the Source section to trigger the redirect:

DECLARE
    l_workspace_id NUMBER;
    l_app_id       NUMBER := 000000; 
    l_page_id      NUMBER := 0;  
    l_url          VARCHAR2(32767);
BEGIN

    l_workspace_id := APEX_UTIL.FIND_SECURITY_GROUP_ID(p_workspace => 'ABC_APEX');

    APEX_UTIL.SET_SECURITY_GROUP_ID(p_security_group_id => l_workspace_id);

    l_url := APEX_UTIL.PREPARE_URL(
        p_url => 'f?p=' || l_app_id || ':' || l_page_id || ':',
        p_checksum_type => 'SESSION'
    );

    owa_util.redirect_url(l_url);

    apex_application.stop_apex_engine;
END;	

However, when the external link calls the ORDS handler path, this is the error I get:

I had looked at similar 555 errors on the forum but they dealt with different ORAs. Is there any obvious step I am missing in the PL/SQL code? Or a fundamental misunderstanding of ORDS handler configurations? I am still new to APEX. In the Parameters section of the ORDS handler, I have not put anything.

Thanks for your time.