Issue Let's Encrypt: Invalid response, Connection refused

[OllieK]

Hi,
I use the Let's Encrypt Extension. It worked flawless for years, but recently it won't renew my certificate.
I cannot find the exact same problem in this forum or the Plesk knowledge base.

The error message is:

Fehler: Let's Encrypt-SSL/TLS-Zertifikat konnte nicht ausgestellt werden für domain.de. Die Autorisierung dieser Domain ist fehlgeschlagen.
Details
Invalid response from https://acme-v01.api.letsencrypt.org/acme/authz/oXY3XVCffDXpCi_cRDCsKPywev0rfYRhp2gGZBCDPTM.
Details:
Type: urn:acme:error:connection
Status: 400
Detail: Fetching http://www.domain.de/.well-known/acme-challenge/MsZFV8QkjEZR_PuBmUUVS3ro2-ywiwdhZnvRTQ-5ZqA: Connection refused

The interesting part is that I can reach http://www.domain.de/.well-known/acme-challenge/MsZFV8QkjEZR_PuBmUUVS3ro2-ywiwdhZnvRTQ-5ZqA without any problems with my browser.

Any ideas?

Oliver

 

[ChristophRo]

In your case this is an IPv6 problem.
Either you need to make sure your server can be reached via IPv6 or you need to remove the AAAA record for your domain.

Currently, your/this site is not available via IPv6 and thus the LetsEncrypt validation fails, as the LetsEncrypt validation server does not perform any fallback to IPv4

wget http://www.your-real-domain.cc/.well-known/acme-challenge/MsZFV8QkjEZR_PuBmUUVS3ro2-ywiwdhZnvRTQ-5ZqA

--2019-04-10 10:44:50--  http://www.your-real-domain.cc/.well-known/acme-challenge/MsZFV8QkjEZR_PuBmUUVS3ro2-ywiwdhZnvRTQ-5ZqA
Resolving www.your-real-domain.cc (www.your-real-domain.cc)... 2a01:x:x:x:x:x:x:x, 87.b.c.d
Connecting to www.your-real-domain.cc (www.your-real-domain.cc)2a01:x:x:x:x:x:x:x|:80... failed: Connection refused.
Connecting to www.your-real-domain.cc (www.your-real-domain.cc)|87.b.c.d|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 87 [text/plain]
Saving to: âMsZFV8QkjEZR_PuBmUUVS3ro2-ywiwdhZnvRTQ-5ZqAâ

MsZFV8QkjEZR_PuBmUUVS3ro2-ywiwdhZnvRTQ-5ZqA 100%[===========================================================================================>]      87  --.-KB/s    in 0s

2019-04-10 10:44:50 (5.35 MB/s) - âMsZFV8QkjEZR_PuBmUUVS3ro2-ywiwdhZnvRTQ-5ZqAâ saved [87/87]

 

[OllieK]

Thanks a lot! I removed the aaaa record and two hours later it worked.
Now I have to find out why my server could not be accessed by IPv6 ;-)