---
title: "ERR_CERT_DATE_INVALID on Cloudflare: cause and fix"
description: "The Cloudflare edge certificate is valid but the origin certificate behind it expired, so Full (Strict) mode fails on the origin leg."
canonical: "https://lemwatch.com/errors/err-cert-date-invalid/in-cloudflare"
source: "https://lemwatch.com"
---

# ERR_CERT_DATE_INVALID on Cloudflare

> The Cloudflare edge certificate is valid but the origin certificate behind it expired, so Full (Strict) mode fails on the origin leg.

## Why it happens on Cloudflare

 The Cloudflare edge certificate is valid but the origin certificate behind it expired, so Full (Strict) mode fails on the origin leg.

## The fix on Cloudflare

 Check the origin directly by IP with an SSL tool, not through Cloudflare. Renew the origin certificate, or replace it with a 15-year Cloudflare Origin Certificate that cannot silently lapse.

## If that didn't fix it

 Cloudflare has its own failure mode, but ERR_CERT_DATE_INVALID has a wider set of causes. The most common one overall is: The certificate expired and auto-renewal silently stopped.

 Renew immediately. For Let's Encrypt, run the renewal manually and read the output — the usual cause is a failing HTTP-01 challenge after a redirect or firewall change.

## Check your own domain

 The SSL checker returns the exact notAfter date and days remaining for the hostname, which immediately separates 'genuinely expired' from 'your clock is wrong'.

## Frequently asked questions

### Why does ERR_CERT_DATE_INVALID happen on Cloudflare?

 The Cloudflare edge certificate is valid but the origin certificate behind it expired, so Full (Strict) mode fails on the origin leg.

### How do I fix ERR_CERT_DATE_INVALID on Cloudflare?

 Check the origin directly by IP with an SSL tool, not through Cloudflare. Renew the origin certificate, or replace it with a 15-year Cloudflare Origin Certificate that cannot silently lapse.

### What does ERR_CERT_DATE_INVALID mean?

 The certificate the server presented is outside its validity window — almost always expired. Either the certificate genuinely lapsed, or the device's clock is wrong so a valid certificate looks expired.


## Related

- [All causes of ERR_CERT_DATE_INVALID](https://lemwatch.com/errors/err-cert-date-invalid)
- [All website error codes](https://lemwatch.com/errors)
- [ERR_CERT_DATE_INVALID on iPhone](https://lemwatch.com/errors/err-cert-date-invalid/on-iphone)
- [ERR_CERT_DATE_INVALID on Android](https://lemwatch.com/errors/err-cert-date-invalid/on-android)
- [ERR_CERT_DATE_INVALID on Shopify](https://lemwatch.com/errors/err-cert-date-invalid/in-shopify)
- [Free SSL certificate check](https://lemwatch.com/tools/ssl-checker)
- [Lemwatch pricing](https://lemwatch.com/pricing)