That’s actually useful, thanks!
openssl says all good, 1st one (out of 3 bundled) is personal and others are intermediate (which is expected).
And of course i’ve tried it this way, always getting handshake failure - malformed_handshake_data as a response. I fear the root is deeper, maybe some misbehaving elliptic curve or something like that, and that’s not distro-dependent (tried various OSes, erlang versions, including 18.x). It wastes way too much time 
