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_01733/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-8fdf9383-ffd0-4eab-9018-741b76a4f1d4",
      "cw-a367b29f-54b8-4514-b0e5-247a9fdf2c87"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-c6c0e131-3bec-4594-89aa-a4819d02fdb0",
    "manifestId": "https://iiif.participatory-archives.ch/SGV_12S_01733/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": true,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-a367b29f-54b8-4514-b0e5-247a9fdf2c87",
    "loadedManifest": "https://iiif.participatory-archives.ch/SGV_12S_01733/manifest.json"
  }
}