First, follow this tutorial:
https://www.cyberciti.biz/faq/how-to-setup-mariadb-ssl-and-secure-connections-from-clients/

Second, the only thing missing from that tutorial is this: In the client, in the section [client] you have to specify the ssl-cypher. It should look something like this:

[client]
ssl-ca=/etc/mysql/ssl/ca-cert.pem
ssl-cert=/etc/mysql/ssl/client-cert.pem
ssl-key=/etc/mysql/ssl/client-key.pem
ssl-cipher=DHE-RSA-AES256-SHA