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_00958/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-215f7335-832c-49eb-ade2-bf71ec9ea969",
      "cw-846f83b0-7047-4d8b-bc8c-49a3bb0957fb"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-0dc059f5-b03c-423a-8e02-89d514da1f1b",
    "manifestId": "https://iiif.participatory-archives.ch/SGV_12S_00958/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": true,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-846f83b0-7047-4d8b-bc8c-49a3bb0957fb",
    "loadedManifest": "https://iiif.participatory-archives.ch/SGV_12S_00958/manifest.json"
  }
}