Mobile Device Management hinter Nginx reverse Proxy

server {
    listen 8080 ssl;
    server_name ws.example.com;
    location / {
        proxy_pass https://localhost:8080; (Ja doppel ssl)
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade; (funktioniert auch ohne diesen und nächsten header nicht)
        proxy_set_header Connection "upgrade";  
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }

    add_header X-Frame-Options "SAMEORIGIN" always;  
    add_header X-XSS-Protection "1; mode=block" always;  
    add_header X-Content-Type-Options "nosniff" always;  
    add_header Referrer-Policy "no-referrer-when-downgrade" always;  
    add_header Content-Security-Policy "default-src 'self' http: https: data: blob: 'unsafe-inline'" always;  

    proxy_read_timeout 300s;
    proxy_send_timeout 300s;

    access_log /var/log/nginx/ws.example.com.access.log;
    error_log /var/log/nginx/ws.example.com.error.log warn;
    ssl_certificate /etc/letsencrypt/live/ws.example.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/ws.example.com/privkey.pem;
}