Please note that Knot DNS 2.8.x breaks all Knot Resolver versions released so far (<=3.2.1).  The breakage is a bit subtle, and build system won't detect it.

We plan to release an update soon. If you don't want to wait, you can apply a simple patch: https://gitlab.labs.nic.cz/knot/knot-resolver/commit/186f2639

--Vladimir