Configure Nextcloud & Onlyoffice behind a DSM synology reverse proxy

Hello,

I unable to enable onlyoffice with nextcloud behind a dsm synology reverse proxy.
The dsm proxy is used as SSL provider and frontend. Private traffic is therefore in http

My (dsm synology) reverse proxy (IP1 private, mondomain.net) assign requests to 2 machines.

Nextcloud give me the following warning : “you are behind a reverse-proxy and the rewrite variables are not set correctly.”

I don’t know if i have to set header in the proxy, and what i should put in nextcloud config.php.

In DSM proxy you can personalized headers relative to each redirection.
I imagine that nextcloud.mondomaine.net and onlyoffice.mondomaine.net are concerned
I think that i have some inputs to do like

Upgrade $http_upgrade;

Connection $proxy_connection;
X-Forwarded-Host $the_host;
X-Forwarded-Proto $the_scheme;
X-Forwarded-For $proxy_add_x_forwarded_for;

Anyone can help me ? thanks