Today, my site suddenly returned 526 (Invalid SSL Certificate), even though the certificate is still valid:
Found the following certs:
Expiry Date: 2019-04-29 15:09:42+00:00 (VALID: 55 days)
Certificate Path: /some/path/fullchain.pem
Private Key Path: /some/path/privkey.pem
Cloudflare’s SSL setting was usually “Full (Strict)”, and origin’s SSL certificate is provided by letsencrypt.
I had to change the SSL setting to “Full” to make it work again.
Anyone has any idea why this suddenly happened? Thanks.