Administration - Installation - Core: Re (2): ERROR with SAML "Destination in response doesn't match the current URL"

I checked and did all the things you said.

The ilias.ini.php had already the nesessary config set, so no need to change that:
[https]
auto_https_detect_enabled = 1
auto_https_detect_header_name = X_FORWARDED_PROTO
auto_https_detect_header_value = https


I also added the x-forward-proto withing traefik:
      - traefik.http.middlewares.testHeader.headers.customrequestheaders.X-Forwarded-Proto=https
      - traefik.http.routers.ilias.middlewares=testHeader

But still nothing, I can see that the header is applied via the GUI from Traefik.

OH and I can see in the log that the setting is applied:
HTTP_X_FORWARDED_FOR     : 130.180.1.38
HTTP_X_FORWARDED_HOST    : ilias.mediadesign.de
HTTP_X_FORWARDED_PORT    : 443
HTTP_X_FORWARDED_PROTO   : https

I also checked under general the HTTP Path, and it's set to https://ilias.mediadesign.de, the host on the other side doesn't specify a protocol, ilias.mediadesign.de.

Is there a way that I check that the x-forward-proto is working?