HTTP 451 Unavailable For Legal Reasons vs 526 Invalid SSL Certificate
HTTP 451 (Unavailable For Legal Reasons) is a 4xx Client Error response, while 526 (Invalid SSL Certificate) is a 5xx Server Error response. 451 indicates that the server is denying access to the resource as a consequence of a legal demand. Named after Ray Bradbury's Fahrenheit 451. In contrast, 526 means that cloudflare-specific. The origin's SSL certificate could not be validated.
Description
The server is denying access to the resource as a consequence of a legal demand. Named after Ray Bradbury's Fahrenheit 451.
When You See It
When content is blocked due to court orders, GDPR requests, or government censorship.
How to Fix
No technical fix. The block is legally mandated. Contact the site operator for details.
Description
Cloudflare-specific. The origin's SSL certificate could not be validated.
When You See It
When using Cloudflare Full (Strict) mode with an invalid origin certificate.
How to Fix
Install a valid SSL certificate on the origin, or use Cloudflare Origin CA certificate.
Key Differences
451 is a 4xx Client Error response, while 526 is a 5xx Server Error response.
HTTP 451: The server is denying access to the resource as a consequence of a legal demand. Named after Ray Bradbury's Fahrenheit 451.
HTTP 526: Cloudflare-specific. The origin's SSL certificate could not be validated.
You encounter 451 when when content is blocked due to court orders, GDPR requests, or government censorship.
You encounter 526 when when using Cloudflare Full (Strict) mode with an invalid origin certificate.
When to Use Which
For 451 (Unavailable For Legal Reasons): No technical fix. The block is legally mandated. Contact the site operator for details. For 526 (Invalid SSL Certificate): Install a valid SSL certificate on the origin, or use Cloudflare Origin CA certificate.