Hi Hans,
currently, you opened the OpenSSL command line tool, via command openssl. However, that’s not required.
Just open your terminal (shell, bash, zsh) and use the full command with your URL.
$ openssl s_client -connect brokerurl.s2.eu.hivemq.cloud:8883 -showcerts < /dev/null 2> /dev/null | sed -n ‘/BEGIN/,/END/p’ > server.pem
The other arguments in this command are:
-showcerts → shows the full certificate chain
< /dev/null 2> /dev/null → closes the command and redirects stderr
sed -n ‘/BEGIN/,/END/p’ → finds the begin and end of each certificate
> server.pem. → redirects the output to the file server.pem
Kind regards,
Dominic