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_01944/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-1b632e91-f1bd-4039-be58-f016556fe570",
      "cw-4548482d-ec2e-49e4-b6cd-1b526f1d97c7"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-5b761b7c-6316-4d3c-9e6f-599376ecc881",
    "manifestId": "https://iiif.participatory-archives.ch/SGV_12S_01944/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": true,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-4548482d-ec2e-49e4-b6cd-1b526f1d97c7",
    "loadedManifest": "https://iiif.participatory-archives.ch/SGV_12S_01944/manifest.json"
  }
}