On March 4, 2020, about 3 million SSL certificates issued by Let’s Encrypt will be revoked due to a Certificate Authority Authorization (CAA).
This represents about 2.6% of the 116 million certificates issued by Let’s Encrypt are active.
Let’s Encrypt cannot determine when these certificates were revoked, but the earliest will start at UTC 00:00.
If your hosting provider issues an SSL certificate for your website, they will usually be contacted by Let’s Encrypt first and will resolve the issue for you. Many website owners have received notifications from hosting providers about this issue.
If you generate your own SSL certificate from Let’s Encrypt, you will need to update the certificate if it is affected.
Clearly in this incident, Let’s Encrypt was very transparent when determining the error on its side as well as reporting the issue to the CA. CouponTree will still rely on Let’s Encrypt next time.