To whom it may concern. Someone keeps trying to break in my Wordpress site to install unauthorized SSL certificates on a fake sub domain. What you are trying to do is actually theft and it needs to stop! Someone from customer service needs to hurry up and email me ASAP!!!
that may be a problem of your DNS provider.
Your domain name is required.
And: It’s not possible to break your Wordpress via a subdomain.
PS: There is another simple solution: Your server is hacked.
Then you have to fix it. That’s not a Letsencrypt problem.
If this is the result you desire, perhaps you should contact a company of whom you are a customer. Ideally, a company who’s actually involved with the situation–perhaps your web host. But whatever’s going on (and your post really doesn’t give any understandable explanation of that), it’s hard to see how you might think, even for a moment, that it has anything to do with the Let’s Encrypt services of which you are not a customer.