This is a classic IPv4 vs. IPv6 case. Your DNS records include an IPv6 record for your site, which Let’s Encrypt uses, but the site available in IPv4 and IPv6 is not the same site.
This is a classic IPv4 vs. IPv6 case. Your DNS records include an IPv6 record for your site, which Let’s Encrypt uses, but the site available in IPv4 and IPv6 is not the same site.