DuckDNS Let's Encrypt configuration issues

Hi, I’m a new HA user and currently have HA installed on a NUC via VirtualBox. I have everything up and running. I’m also using Unifi and have ports 443, 80, 8123 forwarded to the IP address of my HA. I can access the HA using duckdns with regular HTTP from outside my home but not HTTPS. I currently have duckdns installed and let’s encrypt installed as addons in my HA. I guess I just don’t know what the next step is to get the SSL working. I’ve read some things on certbot but don’t really understand how to install it. Is that what I need to make SSL happen? Do I need to change the challenge in the Let’s Encrypt configuration to https instead of http?
When I try to use https to get to my HA from outside my network it says "This site can’t provide a secure connection. #######.duckdns.org sent and invalid response. ERR_SSL_PROTOCOL_ERROR

Kinda lost and looking for some advice. Thanks in advance!