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_00916/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-bb55e8c5-584a-4da0-814e-1b81467afeef",
      "cw-a521f7e1-9292-4485-aec6-fac62882af4d"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-89f84574-29d7-4300-9c03-a6f300173e53",
    "manifestId": "https://iiif.participatory-archives.ch/SGV_12S_00916/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": true,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-a521f7e1-9292-4485-aec6-fac62882af4d",
    "loadedManifest": "https://iiif.participatory-archives.ch/SGV_12S_00916/manifest.json"
  }
}