The recent surprise revocation of LetsEncrypt certificates brought down all the sites I was monitoring with UptimeRobot and they have been down for quite some time without the monitor reporting an issue.
It would seem that if expiry is considered a failure, revocation should also.
Not and idea Frantisek, deviating from the certificate validity standard.
This is super bad in my opinion. Your monitor system does SSL health check but seems to only check expiration dates. Please add revoked to the list of failures!