Use cert-manager with Let's Encrypt® Certificates Tutorial: Automatic Browser-Trusted HTTPS
У вашего броузера проблема в совместимости с HTML5
Let's Encrypt® provides free browser-accepted TLS Certificates and an API to automate against. Luckily there's the amazing cert-manager tool, which we can use to do all the communication with Let's Encrypt's ACME API based on Kubernetes Resources. Learn how to fully automatically obtain and renew TLS certificates that will be shown as "Secure" in your favorite browser.
Let's Encrypt® is a trademark of the Internet Security Research Group. All rights reserved