Mirador viewer

SyntaxError: Unexpected token '<', "<!DOCTYPE "... is not valid JSON

{
  "manifest": {
    "error": "SyntaxError: Unexpected token '<', \"<!DOCTYPE \"... is not valid JSON",
    "id": "https://archives.law.virginia.edu/node/30216/manifest",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-96a202dc-7a49-4b11-875e-b920d28860ae",
      "cw-961a6d66-cbfd-452a-907d-e4cb333c93e0"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-af5906a7-a6b0-4def-bc2f-0d821e24f87e",
    "manifestId": "https://archives.law.virginia.edu/node/30216/manifest",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-961a6d66-cbfd-452a-907d-e4cb333c93e0",
    "thumbnailNavigationPosition": "far-bottom"
  }
}