Hi @david_ally,
Kolibri serves ZIP content from a different port, for security reasons. Therefore if you run Kolibri behind a reverse proxy, you must account for this in your nginx and Kolibri configurations.
You’ll need to configure the ZIP_CONTENT_ORIGIN and/or ZIP_CONTENT_PORT options in your Kolibri’s options.ini file.
If you use kolibri-server without SSL, no further configuration is required. Here’s a similar thread where SSL is involved: Studio content invalid response
Regards,
Blaine