Challenge failed for domain (domain unauthorized)

[Julien.MGD]

My domain is:

gnrb.fr

I ran this command:

sudo /usr/local/bin/certbot-auto certonly --csr request.csr --no-bootstrap

It produced this output:

Plugins selected: Authenticator standalone, Installer None
Performing the following challenges:
http-01 challenge for gnrb.fr
Waiting for verification…
Challenge failed for domain gnrb.fr
http-01 challenge for gnrb.fr
Cleaning up challenges
Some challenges have failed.

IMPORTANT NOTES:

• The following errors were reported by the server:

  Domain: gnrb.fr
  Type: unauthorized
  Detail: Invalid response from
  http://gnrb.fr/.well-known/acme-challenge/p4Zlq_VVTjaaaOT0cI6SXIhfUoIj5k7kHy_hHXsg8gQ
  [217.182.87.205]: “\r\n404 Not
  Found\r\n\r\n

  404 Not
  Found

  \r\n

  ---

  nginx\r\n”

  To fix these errors, please make sure that your domain name was
  entered correctly and the DNS A/AAAA record(s) for that domain
  contain(s) the right IP address.

My web server is : tomcat 8.5.50

The operating system my web server runs on is : debian 9

I can login to a root shell on my machine : yes

The version of my client is 0.28.0

[9peppe]

@Julien.MGD

Authenticator standalone

@Julien.MGD

404 Not
Found

nginx

You can't use --standalone if nginx is already listening on your port 80.

You should use --webroot or --nginx

[Julien.MGD]

Another instance of Certbot is already running.

[9peppe]

I don’t understand. Please tell me more.