According to the docs, there’s a limit of 20 certificates per domain per week.
The docs also state that “Also note: the order of renewals and new issuances matters. To get the maximum possible number of certificates, you must perform all new issuances before renewals during a given time window.”
From when to when does this window run? Is that monday through sunday, sunday through saturday? We’re using LE quite intensively over the past year and are currently at the point where we probably have around 200 hosts with a certificate. Given that certs are renewed once they go below 30-days validity, that gives on average roughly 28 domains that need to be renewed each week. That’s not a problem for renewals, but we regulary run agains the limit when registering a new host. So we scheduled the renewals to run on saturday thinking it was near the end of the week, but appearantly that doesn’t work since today is monday, and we’ve hit the limit already (we had 4 renewals on saturday, and 2 on sunday).