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:2750/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-4dffa03e-87bd-4919-a263-6f288d9d5f5e",
      "cw-7a69b021-00d2-4e14-96e5-b6c5c2c8f085"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-2fa8a0aa-268a-4f3b-b8a8-400da9e8ac17",
    "manifestId": "https://cdm16022.contentdm.oclc.org/iiif/nemhc:2750/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-7a69b021-00d2-4e14-96e5-b6c5c2c8f085"
  }
}