Need Help HTTPS NGINX Revers Proxy


my reverse proxy redirects SSL to http://ip.
everything went fine, but the callback URL in Zammad for 365 ist also http:/xyz and we need to migrate to 365.

Do I need to run Zammad itself in https mode to get an https:// callback uri?

How can i get it to work without Zammad itself having correct ssl certificates, because of the nginx reverse proxy?