Onlyoffice - Documents not saved

Hm… Maybe my config helps you… But this is for subdomains.

Nginx:

server {
        listen       80;
        server_name  doc.domain.com;
    return 301 https://$host$request_uri;
    }

server {
    listen 443;
    server_name doc.domain.com;

####

    ssl on;
    ssl_protocols TLSv1.2;
    ssl_ciphers AES256+EECDH:AES256+EDH:!aNULL;
    ssl_dhparam /etc/ssl/certs/dhparam.pem;
    ssl_ecdh_curve secp384r1;
    ssl_prefer_server_ciphers on;
    ssl_session_cache shared:SSL:10m;
    ssl_session_timeout 10m;
    ssl_certificate /etc/letsencrypt/live/domain.com-0002/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/domain.com-0002/privkey.pem;
    ssl_stapling on;
    ssl_stapling_verify on;

    add_header Strict-Transport-Security "max-age=31536000; includeSubDomains";
    add_header X-Content-Type-Options nosniff;

    gzip off;

    server_tokens off;

     location / {
        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;
        proxy_pass              http://localhost:8083/;
     }
}

seahub_settings.py

# Enable Only Office
ENABLE_ONLYOFFICE = True
VERIFY_ONLYOFFICE_CERTIFICATE = False
ONLYOFFICE_APIJS_URL = 'https://doc.domain.com/web-apps/apps/api/documents/api.js'
ONLYOFFICE_FILE_EXTENSION = ('doc', 'docx', 'ppt', 'pptx', 'xls', 'xlsx', 'odt', 'fodt', 'odp', 'fodp', 'ods', 'fods')

And I start docker via

sudo docker run -i -t -d -p 8083:80 onlyoffice/documentserver

//edit: I just remember this thread. Someone else with that problem: