TypeError: Failed to fetch

{
  "manifest": {
    "error": "TypeError: Failed to fetch",
    "id": "http://jaegerstaetter-test.literaturtirol.at/omekas/iiif/2/451/manifest",
    "isFetching": false
  },
  "window": {
    "autoScrollAnnotationList": true,
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-555188f5-36e6-4221-a51d-91bc937ebe08",
      "cw-7245d98d-7577-4702-b5e5-9a79e0e0ec18"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-14d8723e-f370-4921-9341-6239868fa4ca",
    "manifestId": "http://jaegerstaetter-test.literaturtirol.at/omekas/iiif/2/451/manifest",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-7245d98d-7577-4702-b5e5-9a79e0e0ec18",
    "loadedManifest": "http://jaegerstaetter-test.literaturtirol.at/omekas/iiif/2/451/manifest"
  }
}