Loop Detected

5xx Server Error

ELI5

The server followed references while walking through folders and found a cycle, so it stopped instead of going in circles forever.

Use 508 when a WebDAV operation fails because the server detected an infinite loop while traversing resources.

•Return 508 when a recursive or Depth: infinity operation cannot finish due to cyclic bindings or references
•Use it when the entire operation fails because loop detection is required to prevent unbounded traversal
•WebDAV Depth: infinity operations encounter cyclic bindings or recursive references
•Collection traversal would loop forever without explicit detection
•The server must stop the entire operation because the requested graph of resources is cyclic

•Track visited resources or bindings during traversal so loops are detected deterministically
•Prefer 208 Already Reported inside Multi-Status when you can complete the response safely without repeating members

•No status-specific header is required; standard WebDAV response metadata may still apply

•A body is recommended; explain that a cyclic reference or traversal loop was detected and include enough safe detail for operators or clients to find the offending structure

•Do not use 508 for ordinary deep trees that are merely slow but not cyclic
•Do not use 508 when duplicate suppression with 208 Already Reported would let the operation succeed
•The server can complete the operation and suppress duplicates inside a Multi-Status response (consider 208 Already Reported)
•A single resource is locked or unavailable for other reasons (use a more specific WebDAV status such as 423 Locked)
•Generic server failures unrelated to cyclic traversal (use 500 Internal Server Error or another specific 5xx)

Request:PROPFIND https://api.example.test/collection

Response:

508 Loop Detected

# Headers
Content-Type: application/json

# Body
{
  "error": "loop_detected"
}

The server discovered a reference cycle while enumerating the collection tree and aborted the request.

I did multiple things for you - some worked, some didn't. Here's a detailed report of what happened to each item.

The server is saying, 'I already told you about this item earlier in the same detailed report, so I’m not repeating it.'

I don't have enough storage space left to save what you're trying to upload. My disk is full!