Does anyone know how to use "Collabora Online - Built-in CODE Server" as a caddy reverse proxy?

I know caddy basically supports websockets but there seems to be something wrong.
Oh, and I’m using the docker version. {
redir /.well-known/carddav /remote.php/dav 301
redir /.well-known/caldav /remote.php/dav 301
redir /.well-known/webfinger /index.php/.well-known/webfinger 301
redir /.well-known/nodeinfo /index.php/.well-known/nodeinfo 301
reverse_proxy {
transport http {
request_body {
max_size 4096MB
header {
# disable FLoC tracking
Permissions-Policy interest-cohort=()

     # enable HSTS
     Strict-Transport-Security max-age=31536000;

    # keep referrer data off of HTTP connections
     Referrer-Policy no-referrer-when-downgrade


Please take a look at Apache config and NGINX issues it should be not hard to adopt for caddy…

I’m confused about both suggestions…