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_01943/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-3b9200bd-95e7-4b1d-ba4a-77cf9ee5a01b",
      "cw-dc0982a0-5293-41d6-9ce3-cb84d92cf038"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-1a3fdfcd-9c2d-45c2-b282-6f891388e7ab",
    "manifestId": "https://iiif.participatory-archives.ch/SGV_12S_01943/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": true,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-dc0982a0-5293-41d6-9ce3-cb84d92cf038",
    "loadedManifest": "https://iiif.participatory-archives.ch/SGV_12S_01943/manifest.json"
  }
}