According to slow fog news, Let's Encrypt software bug caused 3 million certificates to be revoked on March 4, 2020 (today)! Let's Encrypt Due to a bug in the back-end code, the Let's Encrypt project will revoke more than 3 million TLS certificates. The detail is that the bug affected Boulder, and the Let's Encrypt project used the server software to authenticate users and their domains before issuing a TLS certificate.
The SlowMist security team reminds: There are many sites or internal systems in the digital currency industry that use Let's Encrypt self-signed certificates for security purposes. Please confirm in time if they are affected. If there is any impact, please update the certificate in time to avoid unpredictable risks. Attach online verification certificate is affected: https://checkhost.unboundtest.com