TypeError: Failed to fetch

{
  "manifest": {
    "error": "TypeError: Failed to fetch",
    "id": "https://dam.sma.unibo.it/smaunibo/containers/4DewEKn/manifest",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-42ecbfd0-692d-44c6-b709-1f0475de5af6",
      "cw-423655ee-3b41-45dd-89fd-a555897ad5c6"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-0c3f482f-778b-4496-a62a-5f9d20b9df17",
    "manifestId": "https://dam.sma.unibo.it/smaunibo/containers/4DewEKn/manifest",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-423655ee-3b41-45dd-89fd-a555897ad5c6",
    "thumbnailNavigationPosition": "far-bottom"
  }
}