A private, inaccessible, IANA/IETF-reserved IP address was found for bbb.mahale-ggmbh.de. Let's Encrypt will always fail HTTP validation for any domain that is pointing to an address that is not routable on the internet. You should either remove this address and replace it with a public one or use the DNS validation method instead.
fe80::4cd3:54ff:fee3:105c
A and AAAA records found for this domain
bbb.mahale-ggmbh.de. 0 IN A 45.146.254.209
bbb.mahale-ggmbh.de. 0 IN AAAA fe80::4cd3:54ff:fee3:105c
1 Certificates contributing to rate limits for this domain
Serial: 316664924018216221731446946161782547698575
NotBefore: 2023-02-16 13:23:24 +0000 UTC
Names: [chat.mahale-ggmbh.de]