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_01991/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-5de86f28-9658-4cb7-b302-3549a768b12a",
      "cw-2f6c674c-8030-4df6-9b0b-4e57cf3b84c7"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-06d21d62-8f69-4c52-91e3-1bbc4b4df7e5",
    "manifestId": "https://iiif.participatory-archives.ch/SGV_12S_01991/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": true,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-2f6c674c-8030-4df6-9b0b-4e57cf3b84c7",
    "loadedManifest": "https://iiif.participatory-archives.ch/SGV_12S_01991/manifest.json"
  }
}