Hi Marco,
You can create the Server Certificate file using the command openssl s_client as described in the community’s Frequently Asked Questions, like this:
openssl s_client -connect 4ad85b7fade04d07911be2ac1da2f5e4.s2.eu.hivemq.cloud:8883 -showcerts < /dev/null 2> /dev/null | sed -n '/BEGIN/,/END/p' > server.pem
Let me know if that helps!
Kind regards,
Dasha from HiveMQ Team