We are currently changing the way how we proxy the MariaDB port 3306 into the user network namespaces. During the migration which is part of the rollout, an unexpected error happened which we are currently fixing. Availability of the port will be restored soon.
MariaDB service itself is unaffected and still reachable through the Unix socket, which is the way we suggest to use in our manual, so most users should be unaffected, only those who use the TCP port instead of the Unix socket.