Hi, this is a rate limit at the Let’s Encrypt side, if you check the certificate transparency logs you can see you’ve generated a bunch of certificates recently: https://transparencyreport.google.com/https/certificates?hl=en&cert_search_auth=&cert_search_cert=&cert_search=include_subdomains:false;domain:mail.pixel8.net&lu=cert_search
This rate limit will reset within 7 days: https://letsencrypt.org/docs/rate-limits/