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:2799/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-18365ca3-23d9-43ae-b025-7a836ee38830",
      "cw-d73bdc95-5a7b-4405-b556-2425e75e2d56"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-36394275-e268-416e-8f76-a69c29d0fd52",
    "manifestId": "https://cdm16022.contentdm.oclc.org/iiif/nemhc:2799/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-d73bdc95-5a7b-4405-b556-2425e75e2d56"
  }
}