You can always ignore this error if:
You haven't generated any Letsencrypt Certificate on your server.
OR
You're using Cloudflare Origin SSL Certificates.
By default, the WordOps Backend (:22222) uses the self-signed certificates which obviously doesn't support SSL Stapling. Whenever you issue a Letsencrypt certificate for any site on your server, WordOps configures the new certificate for the WordOps backend and ssl_stapling
warning is removed.