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_00922/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-d2a74181-2a5e-4a2d-b601-8df347c3e2a6",
      "cw-38c52f5b-4e0a-4ada-95be-8cd8f35b4e24"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-63a0e868-8e2e-4a53-bf56-074b1998e6f2",
    "manifestId": "https://iiif.participatory-archives.ch/SGV_12S_00922/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": true,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-38c52f5b-4e0a-4ada-95be-8cd8f35b4e24",
    "loadedManifest": "https://iiif.participatory-archives.ch/SGV_12S_00922/manifest.json"
  }
}