Mirador Viewer

TypeError: Failed to fetch

{
  "manifest": {
    "error": "TypeError: Failed to fetch",
    "id": "https://api.digitale-sammlungen.de/iiif/presentation/v2/bsb00129020_00731_u001/manifest",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-123636cb-de84-43eb-8e12-2c6daedd0cbb",
      "cw-85d472c7-a226-4a48-ab82-349180eafce9"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-40a8b89a-1cd0-487a-8d69-890dfbda3e0b",
    "manifestId": "https://api.digitale-sammlungen.de/iiif/presentation/v2/bsb00129020_00731_u001/manifest",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": true,
    "sideBarPanel": "calendar",
    "thumbnailNavigationId": "cw-85d472c7-a226-4a48-ab82-349180eafce9",
    "thumbnailNavigationPosition": "far-right",
    "allowClose": false,
    "calendarNavigation": {
      "issueId": "bsb00129020_00731_u001",
      "navDate": "1876-04-25",
      "multId": "bsbmult00000011",
      "lastSearchUrl": null
    },
    "canvasIndex": -1,
    "dfgViewerUrl": "https://dfg-viewer.de/show?tx_dlf%5Bid%5D=https%3A%2F%2Fapi.digitale-sammlungen.de%2Fdfg%2Fmets%2Fmods%2Fv1%2Fdigitalobjects%2Fidentifier%2Fmdz-obj-child%3Absb00129020_00731_u001",
    "loadedManifest": "https://api.digitale-sammlungen.de/iiif/presentation/v2/bsb00129020_00731_u001/manifest",
    "shiftBookView": false,
    "switchCanvasOnSearch": true,
    "view": "book"
  }
}