The Expired Certificate
It's 3 AM. An expired SSL certificate is taking down your telehealth platform.
The Scenario
A telehealth startup's SSL certificate expired overnight. Mobile apps are refusing to connect, the website shows security warnings, and patients can't access critical health services. The certificate was supposed to auto-renew but didn't. You need to figure out why and get the platform back online before the morning rush.
What You'll Learn
How SSL/TLS certificate expiry affects different clients
Using openssl to inspect certificate chains and expiry dates
Diagnosing certificate auto-renewal failures (Let's Encrypt, ACM)
Setting up monitoring and alerts for certificate expiry
Tools You'll Use
Real-World Context
Expired certificates have taken down Microsoft Teams, Spotify, LinkedIn, and even government services. It's embarrassingly common and completely preventable with proper monitoring.