DuckDuckGo does not list our website anymore ⇒ search on the website is broken

For example:

https://duckduckgo.com/?q=usb&sites=tails.boum.org&ia=web

I tried from Firefox and Tor Browser, so it's not related to my location.

It's not broken for Qubes: https://duckduckgo.com/?sites=qubes-os.org++-site%3Aforum.qubes-os.org&q=secure&ia=web

Or the EFF: https://duckduckgo.com/?q=site%3Aeff.org+privacy&t=ha&va=j&ia=web

Maybe because we're a subdomain of boum.org and boum.org is unavailable now: https://boum.org/.