Looking at the DNS record for the primary domain (xxxxx.io - not sharing publicly without your permission), it doesn’t seem to be pointing to us. The onrender subdomain is working as expected. Can you verify the DNS record is correct?
This is something that needs to be configured through your DNS provider rather than within Render. We have detailed instructions here. The tl;dr of it is that you will want an A record pointing to 216.24.57.1 for the apex domain.