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Tag: ssl

Let’s Encrypt – Troubleshooting

Published by marisabel on August 24, 2025 
Details 
Could not issue a Let's Encrypt SSL/TLS certificate for [URL]. Authorization for the domain failed. Details Invalid response from https://acme-v02.api.letsencrypt.org/acme/authz....... Details: Type: urn:ietf:params:acme:error:connection Status: 400 Detail: [IPV6] Fetching [...]  Timeout during connect (likely firewall problem)

Checklist:

  1. check IPv6 on DNS : if on, remove. If off, add it.
  2. Remove HTTP → HTTPS redirection temporarily
  3. Check if ports 80 and 443 are allowed through firewall (specially 443)

LOG:

24/8/25 First issue was the #1, second issue was #3, now it was #2. We’ll see if it now stays stable.

Plesk CMS Documentation

Published by marisabel on January 2, 2025

Opening FTP:

Open ports 21 and 49152-65535 ranges: 

sudo firewall-cmd --permanent --add-port=49152-65535/tcp
sudo firewall-cmd --permanent --add-port=49152-65535/udp
sudo firewall-cmd --permanent --add-port=21/tcp
sudo firewall-cmd --reload

SLL Let’s Encrypt:

Always remove: 

Redirect visitors from HTTP to HTTPS via a SEO friendly 301 redirect