Maybe bcause you use a cloudflare DNS? xD there are mirrors tho: https://git.kescher.at/dCF/deCloudflare/src/branch/master/readme/en.md

They have a separate repository for the server.

Well, it’s still pretty rough because it’s in early development stage, but blazingly fast thanks to Rust (and Dart?). And seeing how active development is right now gives good hopes.

The real FOSS alternative to Notion is called AppFlowy. And it already has a docker.