Be sure the IP is current in duckdns and that port 80 is being allowed through and accepted.
IP currently:
Name: www.davidhallows.duckdns.org
Address: 92.30.233.43
Current Port 443 response:
openssl s_client -connect 92.30.233.43:443
CONNECTED(00000134)
140:error:1408F10B:SSL routines:ssl3_get_record:wrong version number:ssl\record\ssl3_record.c:250:
---
no peer certificate available
---
No client certificate CA names sent
---
SSL handshake has read 5 bytes and written 176 bytes
Verification: OK
---
New, (NONE), Cipher is (NONE)
Secure Renegotiation IS NOT supported
Compression: NONE
Expansion: NONE
No ALPN negotiated
SSL-Session:
Protocol : TLSv1.2
Cipher : 0000
Session-ID:
Session-ID-ctx:
Master-Key:
PSK identity: None
PSK identity hint: None
SRP username: None
Start Time: 1573921423
Timeout : 7200 (sec)
Verify return code: 0 (ok)
Extended master secret: no
---