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_00964/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-b80bd04a-9809-44f5-a1c0-14e6e8a60b6a",
      "cw-9491e99c-0f67-4ec4-b4a1-28cf833b9446"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-2aa1c905-beca-4466-9639-ea63d8fbf980",
    "manifestId": "https://iiif.participatory-archives.ch/SGV_12S_00964/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": true,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-9491e99c-0f67-4ec4-b4a1-28cf833b9446",
    "loadedManifest": "https://iiif.participatory-archives.ch/SGV_12S_00964/manifest.json"
  }
}