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_00963/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-85ae823a-49d8-45c8-8084-cf8b8f74ef5a",
      "cw-3724af21-b22d-4c1e-a50d-191b013b6675"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-4b01a488-c6df-42bf-bdfb-be1924c5325c",
    "manifestId": "https://iiif.participatory-archives.ch/SGV_12S_00963/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": true,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-3724af21-b22d-4c1e-a50d-191b013b6675",
    "loadedManifest": "https://iiif.participatory-archives.ch/SGV_12S_00963/manifest.json"
  }
}