Creating a self-signed certificate for example.com
(if you already have a certificate you can skip this step):
openssl req -x509 -newkey rsa:4096 -sha256 -days 365 -nodes \
-keyout cert.key -out cert.crt -extensions ext -config \
<(echo "[req]";
echo distinguished_name=req;
echo "[ext]";
echo "keyUsage=critical,digitalSignature,keyEncipherment";