iseries.world has an A (IPv4) record (99.247.240.88) 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.
Get "http://iseries.world/.well-known/acme-challenge/letsdebug-test": EOF
Trace:
@0ms: Making a request to http://iseries.world/.well-known/acme-challenge/letsdebug-test (using initial IP 99.247.240.88)
@0ms: Dialing 99.247.240.88
@264ms: Experienced error: EOF
A test authorization for iseries.world to the Let's Encrypt staging service has revealed issues that may prevent any certificate for this domain being issued.
99.247.240.88: Fetching http://iseries.world/.well-known/acme-challenge/LxRjhIoQm8hQhEHvZTcm7la7Y_TpnXzeNRiiU9_6ZCw: Error getting validation data