This question is not related to any one domain name.
Environment: Five Ubuntu 16.04 VPS with Certbot Cloudflare DNS plugin installed. Have active WILDCARD certificates on all 5 VPS (*.example.com). Everything works!
From CLI, when “certbot renew” command is issued, it works. Wildcard certificate is renewed successfully.
However, letsencrypt log shows that AUTOMATIC renewal returns the following error:
2019-10-07 10:16:31,468:WARNING:certbot.renewal:Attempting to renew cert (example.com) from /etc/letsencrypt/renewal/example.com.conf produced an unexpected error: RSA is not supported by the backend. Skipping.
This error is the same on each of the 5 VPS!
To summarize, wildcard renewal works manually on all 5 VPS; but auto renewal returns aforementioned error on all 5.
Any ideas about the RSA error?