Let’s Encrypt, the free and open certificate authority has announced the fact that they will start revoking a number of TLS/SSL certificates due to a bug discovered in the 2020.02.29 CAA Rechecking Bug .
The number of affected certificates is estimated to be 2,6% (3,048,289 out of ~116 million). The revocations are starting from 2020-03-04 20:00 UTC with a deadline of 2020-03-05 03:00 UTC.
In order to verify if your certificate is valid, please follow the tool they have provided. Visit https://checkhost.unboundtest.com/ and fill in your website’s address.
If your certificate is affected, head over to the SSL tab within the control panel and re-issue the certificate in order to avoid unpleasant situations. You should also check your e-mails as they have been notifying people about the incident.
The official announcement can be found here along with more details about the on-going situation: Let’s Encrypt Official Announcement