A private, inaccessible, IANA/IETF-reserved IP address was found for srimuang.ddns.net. 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.
192.168.43.70
A and AAAA records found for this domain
srimuang.ddns.net. 0 IN A 192.168.43.70
An internal error occurred while checking the domain
Failed to query certwatch database to check rate limits: pq: canceling statement due to user request
The IANA public suffix is the TLD of the Registered Domain
The TLD for srimuang.ddns.net is: net
The current status.io status for Let's Encrypt
Operational