Mirador viewer

SyntaxError: Unexpected token 'I', "I don't kn"... is not valid JSON

{
  "manifest": {
    "error": "SyntaxError: Unexpected token 'I', \"I don't kn\"... is not valid JSON",
    "id": "https://iiif.participatory-archives.ch/SGV_12S_00147/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-149e594c-c21b-49c9-b93c-e96715f01b9d",
      "cw-54e1366f-54f0-4a95-a87d-ce5d1827184e"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-028e6ef5-bc0a-4b43-93b7-15c1db8eca4f",
    "manifestId": "https://iiif.participatory-archives.ch/SGV_12S_00147/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": true,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-54e1366f-54f0-4a95-a87d-ce5d1827184e",
    "loadedManifest": "https://iiif.participatory-archives.ch/SGV_12S_00147/manifest.json"
  }
}