508
5xx Server ErrorLoop Detected
The server detected an infinite loop while processing the request.
508 Loop Detected is WebDAV giving up because an operation kept referencing itself, like copying a folder into itself with infinite depth. There's a second life for this code, though: shared hosts running LiteSpeed reuse 508 as 'Resource Limit Is Reached', which has nothing to do with loops but is what most people who search for it actually hit.
What 508 looks like on the wire
PROPFIND /dav/projects/ HTTP/1.1 Host: dav.example.com Depth: infinity HTTP/1.1 508 Loop Detected
About 5xx Server Error
The server failed to fulfill a valid request. The problem is on the server side, not the client.
How to fix 508 Loop Detected
- On shared hosting, treat 508 as a resource limit - check CPU and process caps in your hosting panel.
- Look for rewrite or redirect rules that point back at themselves.
- In WebDAV, avoid copying or moving a collection into itself.
Where it's defined
508 Loop Detected is defined in RFC 5842 §7.2. MDN's 508 reference covers browser behavior and examples.