NET::ERR_CERT_DATE_INVALID (certificate expired)
The site’s certificate has expired (or isn’t valid yet) — or the device clock is wrong.
Exact message you may see
certificate has expired
Seen on:
JavaScript
Meaning
Let’s Encrypt certificates last 90 days; failed auto-renewal is the usual cause. A wrong system date on the visitor’s device shows the same error.
Common causes
- Certificate expired (renewal failed)
- Device clock/date wrong
- Old intermediate in the chain expired
⚡ Quick fix
- Renew the certificate and reload the web server
- Fix certbot renewal (check the timer and logs)
- Correct the device date/time
Detailed fix by platform
Linux
sudo certbot renew && sudo systemctl reload nginx
How to diagnose
- Expiry — Check the certificate’s notAfter date
- Clock — Is the device time correct?
🔧 Still not fixed?
Many errors look alike. If the steps above didn’t solve it, one of these is probably what you’re facing:
Similar errors
Most viewed in JavaScript
- TypeError TypeError: Cannot read properties of undefined (reading 'x')
- Failed to fetch TypeError: Failed to fetch / NetworkError when attempting to fetch resource
- module MIME type Failed to load module script: Expected a JavaScript module script but the server responded with a MIME type of "text/html"
Other ways to find it
Where this error sits
Origin: On your device. Errors that are often confused with or caused by this one (click to open):
🧠 Still stuck? Analyze your error
Paste the full message, response headers or stack trace — we'll detect the platform and point to the most likely cause.
💬 What worked for others
No tips yet — did something else fix this for you?
Share what worked for you
Tips are checked by an editor before they appear. Links are removed.
Did this fix work for you?
Report a correction or suggest an improvement
Last updated 9 Oct 2026