TypeError: Failed to fetch

{
  "manifest": {
    "error": "TypeError: Failed to fetch",
    "id": "http://jaegerstaetter-test.literaturtirol.at/omekas/iiif/2/1616/manifest",
    "isFetching": false
  },
  "window": {
    "autoScrollAnnotationList": true,
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-c18bb319-a17b-4636-be4a-063f184e1772",
      "cw-7792d5fe-4713-40f8-a242-649d75b7c90f"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-f06cf21c-0a54-4036-b2e0-58c6c32de95d",
    "manifestId": "http://jaegerstaetter-test.literaturtirol.at/omekas/iiif/2/1616/manifest",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-7792d5fe-4713-40f8-a242-649d75b7c90f",
    "loadedManifest": "http://jaegerstaetter-test.literaturtirol.at/omekas/iiif/2/1616/manifest"
  }
}