Hi all, 

we are using OpenProject via docker. Until last week an nginx worked as https-proxy for the container. For external access we are using an additional dmz-proxy (apache). So the old situation is:

1. LAN----(https)----nginx---(http)---openproject

2. Internet----(https)---apache----(https)----nginx---(http)---openproject

This weekend we have switched from nginx to traefik, so we have the following new situation:

1. LAN----(https)----traefik---(http)---openproject

2. Internet----(https)---apache----(https)----traefik---(http)---openproject

The apache-config is the same in the old and the new situation. LAN works as expected, so I assume both the config of openproject and traefik are fine. 

But access from the internet via apache now results in error 422. Thus I assume there is a difference between the behavior of traefik and nginx and we have to change the apache-config somehow to get it running with traefik. 

The apache-config is real simple:

	SSLProxyEngine On
	ProxyPass        "/"  "https://project.<domain>/"
	ProxyPassReverse "/"  "https://project.<domain>/"
	SSLEngine on

Adding the line

RequestHeader set X-Forwarded-Proto "https"

to the apache config does not change the behavior. 

Does anyone has any idea to fix this?

Thanks, 
Mathias