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_01979/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-3e680f7c-1b6c-443f-924e-8f0f43f665a7",
      "cw-5027fca8-57db-4813-92e0-a7c1f157d0c7"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-41002ce8-d173-4f24-9b3b-5c86180263f0",
    "manifestId": "https://iiif.participatory-archives.ch/SGV_12S_01979/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": true,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-5027fca8-57db-4813-92e0-a7c1f157d0c7",
    "loadedManifest": "https://iiif.participatory-archives.ch/SGV_12S_01979/manifest.json"
  }
}