The reason you get both the SSL error and the “We couldn’t find that page” error is because of DNS caching.
I see you removed the domain name from one account, and then assigned it to a new account. This new account has a different IP address, which means it requires a DNS change to point that subdomain to the new hosting account. You don’t need to do anything for that, everything is handled automatically by us, but it does mean that it will take up to 72 hours for your website to start working on the new domain name.
So there is nothing wrong or broken. What you see is just how the internet works.