It sounds like you’ve hit the let’s encrypt rate limits. It’s hard to figure out how not to use let’s encrypt, so you’re probably still requesting the certificate (but now if the certificate is going to expire, you won’t get a warning via email). If I’m right, then you can
- wait until next week (easy unless you’re impatient)
- use a different domain name (easy, unless you really love your name or are bad at DNS)
- follow the Setting up Let’s Encrypt with Multiple Domains (fairly tricky for a novice)
- pay someone to get help with the multiple domain thing and/or find that it is some other problem