キャッシュが原因で Let's encrypt の証明書自動取得に失敗してしまう

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Processing /etc/letsencrypt/renewal/<certfile>
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Certificate not due for renewal, but simulating renewal for dry run
Plugins selected: Authenticator webroot, Installer None
Simulating renewal of an existing certificate for <certfile>
Performing the following challenges:
http-01 challenge for <domain>
Using the webroot path /srv/http for all unmatched domains.

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Challenges loaded. Press continue to submit to CA. Pass "-v" for more info about
challenges.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Waiting for verification...
Challenge failed for domain <domain>
http-01 challenge for <domain>

Certbot failed to authenticate some domains (authenticator: webroot). The Certificate Authority reported these problems:
  Domain: <domain>
  Type:   unauthorized
  Detail: During secondary validation: The key authorization file from the server did not match this challenge "RdXMpaPW3jLwb0EAb46oGCQliihEMX1ybNP6PxNQWbU.u1DtLliaSTpmmHj9n-vEt4zNg8VW8ZyvHMw1lC0Cb40" != ""

Hint: The Certificate Authority failed to download the temporary challenge files created by Certbot. Ensure that the listed domains serve their content from the provided --webroot-path/-w and that files created there can be downloaded from the internet.

Cleaning up challenges
Failed to renew certificate <domain> with error: Some challenges have failed.