I think you ran those 2 commands without substituting the DOMAIN placeholder and that's why you get the errors later, could you please confirm it? If that's the case, please run these commands again substituting the DOMAIN placeholder
sudo ln -sf /opt/bitnami/letsencrypt/certificates/DOMAIN.key /opt/bitnami/nginx/conf/server.key
sudo ln -sf /opt/bitnami/letsencrypt/certificates/DOMAIN.crt /opt/bitnami/nginx/conf/server.crt
sudo chown root:root /opt/bitnami/nginx/conf/server*
sudo chmod 600 /opt/bitnami/nginx/conf/server*
If you continue getting errors, we have a Support Tool that will gather relevant information for us to analyze your configuration and logs. Could you please execute it on the machine where the stack is running by following the steps described in the guide below?
Please note that you need to paste the code ID that is shown at the end.