Improvement
Recently, Let's Encrypt started generating certificates with a new intermediate (called "R3") in which they decided to stop supporting OCSP (which is one protocol allowing to check for a certificate revocation individually) in favor of CRL (another older protocol allowing to get a list of revoked certificates) for the intermediary certificate.
The library we built to detect certificate revocation only supported OCSP up until now, so after checking your certificate successfully, when checking the intermediary (R3) it failed because it didn't find an OCSP endpoint. Because of this you may have seen this warning recently:
Up until now it was very rare for certificates not to offer OCSP, that's why we didn't implement CRL yet. But this new intermediate from Let's Encrypt (which represents more than 30% of all certificates on updown.io) pushed us to add support for CRL to our library. This is now done and deployed, so this warning on your certificates will disappear soon (at the next test).
Note: this change will also helps with a couple other Certificate Authorities (other than Let's Encrypt) which were already doing this, and also the ones which will follow Let's Encrypt move in the future.
If you still have some OCSP or CRL warnings on your certificates after that, and you're not sure if it's your Certificate Authority's fault, do not hesitate to ask us!