Action required: Let’s Encrypt certificate renewals
TLS-SNI-01 validation is reaching end-of-life. It will stop working
temporarily on February 13th, 2019, and permanently on March 13th, 2019.
Any certificates issued before then will continue to work for 90 days
after their issuance date.
https://community.letsencrypt.org/t/how-to-stop-using-tls-sni-01-with-certbot/83210