An error occurred while attempting to lookup the TXT record on _acme-challenge.rc.fas.harvard.edu . Any resolver errors that the Let's Encrypt CA encounters on this record will cause certificate issuance to fail.
DNS response for _acme-challenge.rc.fas.harvard.edu/TXT did not have an acceptable response code: SERVFAIL
rc.fas.harvard.edu is currently affected by Let's Encrypt-based rate limits (https://letsencrypt.org/docs/rate-limits/). You may review certificates that have already been issued by visiting https://crt.sh/?q=%harvard.edu . Please note that it is not possible to ask for a rate limit to be manually cleared.
The 'Certificates per Registered Domain' limit (50 certificates per week that share the same Registered Domain: harvard.edu) has been exceeded. There is no way to work around this rate limit. The next non-renewal certificate for this Registered Domain should be issuable after 2022-11-16 23:00:11 +0000 UTC (2h15m0s from now).
The current status as reported by the Let's Encrypt status page is Service Disruption as at 2022-11-16 19:34:33.328 +0000 UTC. Depending on the reported problem, this may affect certificate issuance. For more information, please visit the status page.