Update server to gracefully handle nonce rejection (test with Pebble)
From RFC 8555 § 6.5 Replay protection
When a server rejects a request because its nonce value was unacceptable (or not present), it MUST provide HTTP status code 400 (Bad Request), and indicate the ACME error type "urn:ietf:params:acme:error:badNonce". An error response with the "badNonce" error type MUST include a Replay-Nonce header field with a fresh nonce that the server will accept in a retry of the original query (and possibly in other requests, according to the server's nonce scoping policy). On receiving such a response, a client SHOULD retry the request using the new nonce.