Connection timed out error when pointed a different domain to Worker

I have a CF worker setup on work. example .io - it works fine there and on the domain. I tried adding a cname for example .com that points to work. example .io. I get a connection timed out error immediently when accessing it on example .com.

I am trying to allow other domains to simply point a CNAME record at my site and it’ll show my worker

I do NOT want to add this as a route/custom domain to example .com, as this is part of a larger project I’m working on for this use case.

That’s not going to work, then. Like any origin, it needs to be configured to respond to requests for known hostnames.