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_00735/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-cd5ca633-9106-4f57-9cd2-2f95b76d5b26",
      "cw-581d40b7-a035-4d15-a0db-787aa83c140a"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-5864ad3a-2a30-4914-a16b-76e3da00a906",
    "manifestId": "https://iiif.participatory-archives.ch/SGV_12S_00735/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": true,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-581d40b7-a035-4d15-a0db-787aa83c140a",
    "loadedManifest": "https://iiif.participatory-archives.ch/SGV_12S_00735/manifest.json"
  }
}