I control a machine where I can't control DNS or open HTTP port. Is there a way I could pass a LetsEncrypt challenge when I can only accept connections over HTTPS and/or a few other ports? I found that there's "Proof of Possesion" challenge that could perhaps work for me because I already have a wildcard certificate for the domain, but I can't find any docs on this one... Would it work with my use case?
It had, over HTTPS port (443):
But for security reason it's now (mostly) disabled:
TLS-SNI-03 is in progress:
But it's not yet available