It is designed really well and has all of the essential features for a Kanban board. I have been hosting it myself on DigitalOcean for months and I've never had a single problem. The web interface is responsive and mobile-friendly. It is free and open source. The Wekan team has a Gitter and appears very responsive so far.

easy to use, configure. The features are exactly what I need from this kind of software

Maxime has done a great job with Wekan, it's simple to use and clutter free. It behaves quite intuitively, and being open source has the flexibility to be adapted or integrated with other tools in the toolbox.