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/info/p16022coll624/491/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-d161d570-de76-4991-894f-4c34807d8e7d",
      "cw-ce1b9e8c-4982-4998-91ed-f95fa6853ce8"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-0387e8f3-ba6b-4450-86d9-05b7b93fc9ab",
    "manifestId": "https://cdm16022.contentdm.oclc.org/iiif/info/p16022coll624/491/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-ce1b9e8c-4982-4998-91ed-f95fa6853ce8"
  }
}