Mirador viewer

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

{
  "manifest": {
    "error": "SyntaxError: Unexpected token '<', \"<!DOCTYPE \"... is not valid JSON",
    "id": "https://cdm16022.contentdm.oclc.org/iiif/nemhc:2769/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-477d2595-da57-4be2-b6b1-7f1f0651a065",
      "cw-556ef9e8-6201-40a2-9030-90c884d7ecca"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-8cf47423-b35a-41df-8db7-8f9cf9d5db85",
    "manifestId": "https://cdm16022.contentdm.oclc.org/iiif/nemhc:2769/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-556ef9e8-6201-40a2-9030-90c884d7ecca"
  }
}