SAML 2.0 - Failed to verify signature

[Glowsome (Michael Honkoop)]

@techtuga, @fdutenho

Well i think i solved it for a/the most simple setup, i needed to add the directive:

• OIDCXForwardedHeaders X-Forwarded-Host

please see https://forum.checkmk.com/t/howto-cmk-with-oidc-authentication/37168