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WebAuthn Metadata Too Large

URI: https://docs.ankatech.co/errors/webauthn-metadata-too-large
HTTP Status: 413 Content Too Large

When you see this

A platform operator uploaded a FIDO Metadata Service (MDS3) file (PUT /api/v3/admin/platform/webauthn-metadata, replaceWebauthnMetadata) larger than 32 MiB (33,554,432 bytes), the most this deployment accepts. The body is read only one byte past that bound, and the metadata already loaded stays in place.

A genuine MDS3 file is about a third of that size.

Common Causes

  • The wrong file was selected.
  • The file was wrapped or re-encoded before upload (for example, saved as a text file with a different encoding, or inside an archive).

Response Example

{
  "type": "https://docs.ankatech.co/errors/webauthn-metadata-too-large",
  "title": "WebAuthn Metadata Too Large",
  "status": 413,
  "detail": "The metadata BLOB exceeds the maximum accepted size of 33554432 bytes. The stored metadata is unchanged.",
  "instance": "/api/v3/admin/platform/webauthn-metadata",
  "timestamp": 1730000000,
  "extensions": {
    "requestId": "5b2e9c1a-7f3d-4a8e-b6c2-0d9e1f2a3b4c"
  }
}

Content-Type: application/problem+json — the response follows RFC 9457 Problem Details. This is an Admin API body, so the correlation identifier is extensions.requestId; see Error Index & Overview.

How to Resolve

  1. Download the file again from https://mds3.fidoalliance.org/ and upload it exactly as downloaded, as application/jwt.

For full schema definitions, examples, and interactive testing, see the Developer Hub Reference.