It seems that you have removed the domain name from your account, which is why it’s not working anymore.
The epizy.com domain is deprecated, which is why you cannot find it in the subdomains option. And since it’s a subdomain, it obviously cannot be added as a custom domain.
I have added the domain to your account again. However, note that the website directory may be different than it was before. If so, you may need to move your website to the new location.