Use alternative Lets Encrypt validation method
I've been using ISPConfig and at the moment I'm on 3.1.13p1. I use LetsEncrypt SSL certificates and have been getting these emails:
noreply@letsencrypt.org Mon, Mar 11, 9:13 PM (5 days ago)
Hello,
Action may be required to prevent your Let's Encrypt certificate renewals from breaking.
If you already received a similar e-mail, this one contains updated information.
Your Let's Encrypt client used ACME TLS-SNI-01 domain validation to issue a certificate in the past 7 days. Below is a list of names and IP addresses validated (max of one per account):
TLS-SNI-01 validation is reaching end-of-life. It will stop working permanently on March 13th, 2019. Any certificates issued before then will continue to work for 90 days after their issuance date.
You need to update your ACME client to use an alternative validation method (HTTP-01, DNS-01 or TLS-ALPN-01) before this date or your certificate renewals will break and existing certificates will start to expire.
Our staging environment already has TLS-SNI-01 disabled, so if you'd like to test whether your system will work after March 13, you can run against staging: https://letsencrypt.org/docs/staging-environment/
If you're a Certbot user, you can find more information here: https://community.letsencrypt.org/t/how-to-stop-using-tls-sni-01-with-certbot/83210
Our forum has many threads on this topic. Please search to see if your question has been answered, then open a new thread if it has not: https://community.letsencrypt.org/
For more information about the TLS-SNI-01 end-of-life, please see our API announcement: https://community.letsencrypt.org/t/february-13-2019-end-of-life-for-all-tls-sni-01-validation-support/74209
Thank you, Let's Encrypt Staff