Invalid reponse behind pfsense haproxy: recevied at wrong port

[ojsef39]

Describe the bug
I have pfsense behind HAProxy plugin and im trying to figure out how to enable SAML Login with that setup.
When i try to log in, i get the following error:

The response was received at https://pfsense.domain.org:2020/saml2_auth/sso/acs/ instead of https://pfsense.domain.org/saml2_auth/sso/acs/
invalid_response
The response was received at https://pfsense.domain.org:2020/saml2_auth/sso/acs/ instead of https://pfsense.domain.org/saml2_auth/sso/acs/

To Reproduce
Steps to reproduce the behavior:

1. Pfsense behind haproxy plugin on port 2020 (frontend 443)
2. setup saml plugin
3. try to login

Expected behavior
Login works

pfSense Version & Package Version:

• pfSense Version: 2.7.2-RELEASE
• Package Version v1.3.0

Identity Provider Information:

• IdP Name: Zitadel
• IdP Type: Self-Hosted

Thank you very much in advance for all your help :)