Drinko solve your immediate problem with:
rm -f /var/www/technologymegao.online/conf/nginx/ssl.conf
wo site update technologymegao.online --le=purge
service nginx restart
wo site update technologymegao.online --le
The "ssl.conf" is responsible for telling Nginx where the cert lives for a given domain, when you delete it, Nginx will not search for a certificate anymore.
Then you "purge" LE configuration, just in case, and restarts the server. After that, you can add a new cert to your domain.