Revoking certain certificates on March 4 Help - Let's Encrypt Community Support
https://community.letsencrypt.org/t/revoking-certain-certificates-on-march-4/114864

>Due to the 2020.02.29 CAA Rechecking Bug 4.7k, we unfortunately need to revoke many Let’s Encrypt TLS/SSL certificates. We’re e-mailing affected subscribers for whom we have contact information.
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>This post and thread will collect answers to frequently asked questions about this revocation, and how to avoid problems by renewing affected certificates early. If you’re affected, please: thoroughly read this thread, and search the community forum, for an answer to your question. If you don’t find one, please make a new post to the “Help” category, filling in the questions in the template that appears as you compose your post.