X_BODY_TOO_LARGE
Means
request body over the transport ceiling
Typical cause
the request declares or streams more bytes than http.maxRequestBodyBytes, the most this process reads for any route; a signed upload bigger than that cannot be accepted in one request
Fix
send it in parts (storage signPart/completeUpload for an upload), or raise the ceiling: configureHttp({ maxRequestBodyBytes: <bytes> }) in the app's http.ts