To be more explicit about that, ZeroSSL used to use Let's Encrypt certificates but after it was acquired by apilayer, it became its own certificate authority
and indeed, it no longer has any connection with this forum at all (except for some tools that can use both Let's Encrypt and ZeroSSL via the ACME technology, but if you're using ZeroSSL's web interface, that's not one of them).
Let's Encrypt (which this forum is about) doesn't have any official web interface at all. @freessltools.com has recently made a new unofficial one at https://freessltools.com/. If you want to use Let's Encrypt via a web interface, you could consider using that one. The officially recommended way to use Let's Encrypt is by using a web hosting provider that has built-in support for it. There is a list of these at
If you are the administrator of your own VPS or dedicated server, you can also use Let's Encrypt via one of the tools at
These are not as relevant if you're not the system administrator of your web server.
If you do continue using ZeroSSL's tools, @JuergenAuer is right that this forum is no longer the place to get help with them. 