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/p16022coll246/339/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-92470d1a-d20e-4bda-b2b2-260a73a900e4",
      "cw-22b9486c-e85c-4f71-b656-13fb89171eea"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-cb83d93e-fb38-411b-8b93-6ac77b7d1589",
    "manifestId": "https://cdm16022.contentdm.oclc.org/iiif/info/p16022coll246/339/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-22b9486c-e85c-4f71-b656-13fb89171eea"
  }
}