Websites prove their identity via certificates. Firefox does not trust this site because it uses a certificate that is not valid for www.daniellesucher.com.
Error code: MOZILLA_PKIX_ERROR_SELF_SIGNED_CERT
View Certificate
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Followed by: "Site not found"
Because it's blindly following an inadequate heuristic, and not gracefully degrading if it fails - instead, you get comments like these blaming the author. Even though the author never wanted you to use HTTPS in the first place.
> What justification is there for serving HTTPS in a way users can't expect to consume?
Plenty of technical reasons (eg. what the sibling comments mentioned), but most importantly: there's no Internet/Web standard that I'm aware of which would prohibit me from doing so.
For example, you might be running a Tor relay node which would serve the node directory list on :443 to help people bypass firewalls, but also be using it as a useful and legitimate web server in order to prevent organizations from blocking it wholesale.
DreamHost could automatically issue LE certs for their customers but that's not how they do things and don't enable it without customer approval.
It is impossible for DreamHost to not give you an error in this case. You connected directly to port 443 with a name that they don't have a certificate for. They could just close the connection but I don't think that would be an improvement on the situation.