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_00904/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-c13423d2-8c61-48b8-abaf-72f0196d147c",
      "cw-b4ab999c-049b-4b2d-b0af-5d6cb960950d"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-3cb64937-4334-41d5-8d79-f9ef1400ef78",
    "manifestId": "https://iiif.participatory-archives.ch/SGV_12S_00904/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": true,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-b4ab999c-049b-4b2d-b0af-5d6cb960950d",
    "loadedManifest": "https://iiif.participatory-archives.ch/SGV_12S_00904/manifest.json"
  }
}