POST Call to AEM from SFDC gives HTTP Error 403

Hi All,

We are loading AEM Forms in an iframe on an AEM web page and form action url is that SFDC Pardot system.

After successful form submission SFDC Pardot system does a POST call to success page(AEM page) which we trying to load in the same iframe but see below error.

HTTP ERROR 403
Problem accessing /global/en/form-success.html. Reason:
Forbidden

We have tried allowing POST in dispatcher filter for below url but still see same issue.

/0182 { /type "allow" /method "POST" /path "/global/en/form-success" /extension "html"}

Dispatcher Access log:

10.43.0.50 "stage-www.xxx.com" brunswick [14/Sep/2020:09:31:30 +0000] "POST /global/en/form-success.html HTTP/1.1" 403 209 "https://go.pardot.com/l/70842/2020-07-14/xxx" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.102 Safari/537.36"

Dispatcher log has below information

[Mon Sep 14 07:20:02 2020] [D] [pid 23527 (tid 140434929665792)] Found farm publishfarm for stage-www.xxx.com
[Mon Sep 14 07:20:02 2020] [D] [pid 23527 (tid 140434929665792)] checking [/global/en/form-success.html]
[Mon Sep 14 07:20:02 2020] [D] [pid 23527 (tid 140434929665792)] request method is neither GET nor HEAD: POST
[Mon Sep 14 07:20:02 2020] [D] [pid 23527 (tid 140434929665792)] cache-action for [/global/en/form-success.html]: NONE
[Mon Sep 14 07:20:02 2020] [D] [pid 23527 (tid 140434929665792)] Creating new socket: 10.43.0.6:4503
[Mon Sep 14 07:20:02 2020] [D] [pid 23527 (tid 140434929665792)] Connected to backend 0 (10.43.0.6:4503)

Any inputs what can be done to fix this issue?

Thanks

Srikanth