No WSS Connection to CollaboraOffice

Hello togehter,

i want to install collabora online office in my Nextcloud. I do not use the docker container so I installed it myself. I have the following construction:

cloud.***.de -> Sophos Reverseproxy (with Lets-Encrypt) -> Ubuntu VM with Nextcloud and Collabora

On the Ubuntu VM is an Nginx Webserver with the following config: (its only a part of the hole config)

        # static files
        location ^~ /loleaflet {
            proxy_pass https://localhost:9980;
            proxy_set_header Host $http_host;
        }

        # WOPI discovery URL
        location ^~ /hosting/discovery {
            proxy_pass https://localhost:9980;
            proxy_set_header Host $http_host;
        }

        # Capabilities
        location ^~ /hosting/capabilities {
            proxy_pass https://localhost:9980;
            proxy_set_header Host $http_host;
        }

        # main websocket
        location ~ ^/lool/(.*)/ws$ {
            proxy_pass https://localhost:9980;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection "Upgrade";
            proxy_set_header Host $http_host;
            proxy_read_timeout 36000s;
        }

        # download, presentation and image upload
        location ~ ^/lool {
            proxy_pass https://localhost:9980;
            proxy_set_header Host $http_host;
        }

        # Admin Console websocket
        location ^~ /lool/adminws {
            proxy_pass https://localhost:9980;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection "Upgrade";
            proxy_set_header Host $http_host;
            proxy_read_timeout 36000s;
        }

When I try to open a document in the cloud the browser console show
Firefox kann keine Verbindung zu dem Server unter wss://cloud.****.de/lool/**** aufbauen.

Does anybody can help me? I’ve tryed the same with an apache webserver. But there the same error occured…

Thank you very much!