`spreed.svg` Asset is loaded from http

Nextcloud version (eg, 12.0.2): docker nextcloud
Operating system and version (eg, Ubuntu 17.04): docker nextcloud
Apache or nginx version (eg, Apache 2.4.25): docker nextcloud behind reverse proxy (caddyserverV1 latest) , behind cloudflare
PHP version (eg, 7.1): docker nextcloud

The issue you are facing:

the asset next.example.com/apps/firstrunwizard/img/apps/spreed.svg
is loaded over http, instead of https as the rest of the site, i have my site configured to upgrade all http connections to https automatically but it refuses to load from https

Is this the first time you’ve seen this error? (Y/N): N