5009: Media source unsupported.

HTTP status: 422.

The address at param answered with a media type the part’s kind does not accept, a body over the kind’s size ceiling, a sticker without a readable WebP container, or a body with no usable Content-Type or with a Content-Encoding. The bytes are held to exactly the rules POST /v1/media applies to the same kind and are never converted, truncated or decoded. Nothing was sent.

• Set kind to match the file the address serves, and serve it under a media type the upload operation documents for that kind.
• Serve the exact file bytes with their Content-Type and no Content-Encoding.
• Keep the file within the kind’s byte ceiling; the ceilings are those of POST /v1/media.