does letsencrypt.org server has any restrictions for private key size?
One of letsencrypt_plugin users has a problem with key size = 8192. I can reproduce this error with a private key generated in following way:
openssl genrsa 8192 > key/keyfile.pem sever responds with an error: “Acme::Client::Error::Unauthorized: No registration exists matching provided key”. Is it correct behavior?