How do I debug a certbot problem?

Howdy! I’m having a bunch of trouble renewing a certificate with certbot. The certificate was issued just fine, but I can’t get renewal to work. Operating system is Debian 10.0 “Buster”. Typical error in my logs is as follows:

Aug 25 01:21:17 green certbot[20840]: Attempting to renew cert ( from /etc/letsencrypt/renewal/ produced an unexpected error: Failed authorization procedure. (http-01): urn:ietf:params:acme:error:connection :: The server could not connect to the client to verify the domain :: Fetching Connection refused. Skipping.
Aug 25 01:21:17 green certbot[20840]: All renewal attempts failed. The following certs could not be renewed:
Aug 25 01:21:17 green certbot[20840]:   /etc/letsencrypt/live/ (failure)
Aug 25 01:21:17 green certbot[20840]: 1 renew failure(s), 0 parse failure(s)
Aug 25 01:21:17 green systemd[1]: certbot.service: Main process exited, code=exited, status=1/FAILURE
Aug 25 01:21:17 green systemd[1]: certbot.service: Failed with result 'exit-code'.
Aug 25 01:21:17 green systemd[1]: Failed to start Certbot.
Aug 25 01:40:58 green sshd[20874]: Disconnected from user root port 54370

My domain is:

I ran this command: nightly automated job, plus tried certbot -v renew and can’t figure out what the output means.

It produced this output:
I can cut and paste portions of the output of certbot -v renew if someone wants them. I’m not sure how to interpret them; some parts make sense, some don’t.

My web server is (include version): lighttpd 1.4.53

The operating system my web server runs on is (include version): see above, Debian 10.0 “Buster”

My hosting provider, if applicable, is: N/A

I can login to a root shell on my machine (yes or no, or I don’t know): yes

I’m using a control panel to manage my site (no, or provide the name and version of the control panel): no

The version of my client is (e.g. output of certbot --version or certbot-auto --version if you’re using Certbot): certbot 0.31.0

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Hi @pmetzger

you have ipv4- and ipv6-addresses and a redirect http -> https. But your ipv6 + https doesn’t work ( ):

Domainname Http-Status redirect Sec. G 301 0.203 A
2001:470:30:84:e276:63ff:fe62:3500 301 0.210 A 200 2.807 B
2001:470:30:84:e276:63ff:fe62:3500 -2 1.313 V
ConnectFailure - Unable to connect to the remote server No connection could be made because the target machine actively refused it [2001:470:30:84:e276:63ff:fe62:3500]:443 301 0.203 A
Visible Content:
2001:470:30:84:e276:63ff:fe62:3500 301 0.206 A
Visible Content: 404 6.157 A
Not Found
Visible Content: 404 Not Found

Ipv6 + http works, ipv6 + https not. And you have a redirect http -> https, so Letsencrypt checks /.well-known/acme-challenge/validation-file via ipv6 + https.

Your error message:

Fetching Connection refused.

Fix your ipv6 + https or (not so good) remove the ipv6 address in your DNS.


Excellent! This is something I can debug, then!


That was the problem! Easily fixed, and now everything seems to have worked with the renewal! Thank you so much, @JuergenAuer!


Happy to read that it had worked.


Issuer not before not after Domain names LE-Duplicate next LE
Let’s Encrypt Authority X3 2019-08-25 2019-11-23 - 1 entries duplicate nr. 1

is your new certificate.


Checked your domain, first with my browser, then online, you don’t use the new certificate:
expires in 9 days - 1 entry

The old certificate is used. Installed? Restartet your server?

That’s peculiar. I’ve restarted the server now; I’m not really sure what was going wrong before, though, because I’m pretty sure I restarted the server earlier. Can you verify that it is now working from your point of view?

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Use the online tool to check your domain. Then you see if the new certificate is online.

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