diff --git a/Containers/nextcloud/entrypoint.sh b/Containers/nextcloud/entrypoint.sh
index b90b4011..858b1f9a 100644
--- a/Containers/nextcloud/entrypoint.sh
+++ b/Containers/nextcloud/entrypoint.sh
@@ -903,11 +903,24 @@ if [ "$EUROOFFICE_ENABLED" = 'yes' ]; then
 
         # Adjust the EuroOffice host if using internal pattern
         if echo "$EUROOFFICE_HOST" | grep -q "nextcloud-.*-eurooffice"; then
+            # Set internal URLs for server-to-server calls via Docker network,
+            # bypassing the public domain which may not resolve inside containers.
+            # DocumentServerInternalUrl: NC -> EuroOffice (direct container port)
+            # StorageUrl: EuroOffice -> NC (via port 23973 which has a matching Caddy server-block)
+            APACHE_CONTAINER_HOST=$(echo "$EUROOFFICE_HOST" | sed 's/-eurooffice$/-apache/')
+            php /var/www/html/occ config:app:set eurooffice DocumentServerInternalUrl --value="http://$EUROOFFICE_HOST:80/"
+            php /var/www/html/occ config:app:set eurooffice StorageUrl --value="http://$APACHE_CONTAINER_HOST.nextcloud-aio:23973/"
             EUROOFFICE_HOST="$NC_DOMAIN/eurooffice"
             export EUROOFFICE_HOST
         fi
 
         php /var/www/html/occ config:app:set eurooffice DocumentServerUrl --value="https://$EUROOFFICE_HOST"
+
+        # Register EuroOffice preview provider in the explicit allowlist.
+        # Use a high fixed index (50) to avoid colliding with AIO's seeded indices (1-7, 23).
+        if ! php /var/www/html/occ config:system:get enabledPreviewProviders | grep -q "Eurooffice"; then
+            php /var/www/html/occ config:system:set enabledPreviewProviders 50 --value="OCA\Eurooffice\Preview"
+        fi
     fi
 else
     # Remove EuroOffice app if disabled and removal is requested