The cryptpad-nginx image is not designed for use with a proxy, it expects to be on public port 443, and this is a problem when I attempted to upgrade to 5.1.0. We should stop using the cryptpad-nginx image and use the cryptpad image instead.

https://github.com/xwiki-labs/cryptpad-docker#standalone-cryptpad

To do this securely, Traefik must set the same CSP headers in the same way that nginx is.