Great. I can 100% reproduce the issue at 0.5.0:
alex at x1 in ~/Downloads/dehydrated (tags/v0.5.0)
$ ./dehydrated -6 -f config -c -x
# INFO: Using main config file config
Processing 80755380.ngrok.io
+ Checking domain name(s) of existing cert... unchanged.
+ Checking expire date of existing cert...
+ Valid till Dec 23 06:36:00 2019 GMT Certificate will not expire
(Longer than 30 days). Ignoring because renew was forced!
+ Signing domains...
+ Generating private key...
+ Generating signing request...
+ Requesting challenge for 80755380.ngrok.io...
+ ERROR: An error occurred while sending post-request to https://acme-staging.api.letsencrypt.org/acme/new-authz (Status 400)
Details:
{
"type": "urn:acme:error:badNonce",
"detail": "JWS has no anti-replay nonce",
"status": 400
}
Upgrade to 0.6.5.