Connecting home assistant and an emby server on a seedbox

hi I have issues connecting Emby and Home assistant.

My emby server is on a UltraCC seedbox. it is running on docker and behind a reverse proxy I believe as I reach it on

I connect my clients to that address and the api is responding well too.

internally it is running on usual ports with auto port mapping enabled

but in the home assistant logs I get a 404 error and cannot connect.

any way to solve this?

thank you