TypeError: Failed to fetch

{
  "manifest": {
    "error": "TypeError: Failed to fetch",
    "id": "http://jaegerstaetter-test.literaturtirol.at/omekas/iiif/2/1168/manifest",
    "isFetching": false
  },
  "window": {
    "autoScrollAnnotationList": true,
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-6f56be59-3b05-4da1-a8e9-2c4a2166f9ca",
      "cw-d4bd0297-ccbd-4265-b1b9-107a6f684d8b"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-2eafaac4-7eac-4328-a9bb-e77df4f60b2a",
    "manifestId": "http://jaegerstaetter-test.literaturtirol.at/omekas/iiif/2/1168/manifest",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-d4bd0297-ccbd-4265-b1b9-107a6f684d8b",
    "loadedManifest": "http://jaegerstaetter-test.literaturtirol.at/omekas/iiif/2/1168/manifest"
  }
}