HTTP 412 Precondition Failed vs 508 Loop Detected
HTTP 412 (Precondition Failed) is a 4xx Client Error response, while 508 (Loop Detected) is a 5xx Server Error response. 412 indicates that one or more conditions in the request headers (If-Match, If-Unmodified-Since) evaluated to false. In contrast, 508 means that the server detected an infinite loop while processing the request (WebDAV).
Description
One or more conditions in the request headers (If-Match, If-Unmodified-Since) evaluated to false.
When You See It
When using conditional requests with ETags and the resource has changed.
How to Fix
Refresh the ETag/Last-Modified value and retry with updated preconditions.
Description
The server detected an infinite loop while processing the request (WebDAV).
When You See It
When WebDAV encounters circular references in bindings.
How to Fix
Fix the circular reference in the WebDAV configuration.
Key Differences
412 is a 4xx Client Error response, while 508 is a 5xx Server Error response.
HTTP 412: One or more conditions in the request headers (If-Match, If-Unmodified-Since) evaluated to false.
HTTP 508: The server detected an infinite loop while processing the request (WebDAV).
You encounter 412 when when using conditional requests with ETags and the resource has changed.
You encounter 508 when when WebDAV encounters circular references in bindings.
When to Use Which
For 412 (Precondition Failed): Refresh the ETag/Last-Modified value and retry with updated preconditions. For 508 (Loop Detected): Fix the circular reference in the WebDAV configuration.