Unable to issue Let's Encrypt certificate for www.example.com: 403 Invalid response

Samuel Figueredo

Updated January 21, 2026 15:22

kb: technical ext: le

Symptoms

The following error appears in Plesk when issuing Let's Encrypt certificate via Domains > example.com > SSL/TLS certificates > Get it free:
CONFIG_TEXT: Could not issue a Let's Encrypt SSL/TLS certificate for example.com.
Details
Invalid response from https://acme-v02.api.letsencrypt.org/acme/authz-v3/4860997820.
Details:
Type: urn:ietf:params:acme:error:unauthorized
Status: 403
Detail: Invalid response from http://www.example.com/.well-known/acme-challenge/BNgVm184hQ4nRblIOjjKkXNAKp5FT2me3ruDFhtqz14 [203.0.113.3]: "<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN">\n<html>\n\t<head>\n\t\t<meta http-equiv="Content-Type" content="text/css; ch"
Domain has IP address 203.0.113.2 in Plesk.
Domain example.com resolves to 203.0.113.2:
# dig example.com +short
203.0.113.2
Domain www.example.com resolves to 203.0.113.3:
# dig www.example.com +short
203.0.113.3
The DNS zone of the domain example.com is hosted on external DNS servers.

DNS misconfiguration. Both example.com and www.example.com should resolve to one IP.

Modify www.example.com DNS record on external DNS servers to make it resolve on Plesk IP address 203.0.113.2.