Renew a Let’s Encrypt certificate installed using bncert-tool or Lego tool

Run the following commands:

sudo /opt/bitnami/ctlscript.sh stop

sudo /opt/bitnami/letsencrypt/lego --tls --email="EMAIL-ADDRESS" --domains="DOMAIN" --path="/opt/bitnami/letsencrypt" renew --days 90

sudo /opt/bitnami/ctlscript.sh start

Source: Amazon knowledge center

https://aws.amazon.com/premiumsupport/knowledge-center/lightsail-bitnami-renew-ssl-certificate/

Hope this helps.