srimuang.ddns.net has an A (IPv4) record (49.230.160.135) but a request to this address over port 80 did not succeed. Your web server must have at least one working IPv4 or IPv6 address.
A timeout was experienced while communicating with srimuang.ddns.net/49.230.160.135: Get "http://srimuang.ddns.net/.well-known/acme-challenge/letsdebug-test": context deadline exceeded
Trace:
@0ms: Making a request to http://srimuang.ddns.net/.well-known/acme-challenge/letsdebug-test (using initial IP 49.230.160.135)
@0ms: Dialing 49.230.160.135
@10000ms: Experienced error: context deadline exceeded
A test authorization for srimuang.ddns.net to the Let's Encrypt staging service has revealed issues that may prevent any certificate for this domain being issued.
49.230.160.135: Fetching http://srimuang.ddns.net/.well-known/acme-challenge/qIdB-qOY2csZMqhX8SGURCPNac4XEHSuJRoYR17NJuU: Timeout during connect (likely firewall problem)