The module mounted a TLS directory nothing fills, so the server could not start
on a mesh that was not raised by the genesis template. The mesh already has a
broker certificate every machine pins by fingerprint and the controller trusts;
serving the new bus with it means no pin changes when a machine moves and there
is no second certificate to be wrong about. No ca_file: the directory has none,
and a pinning client checks the leaf and nothing else.