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/p16022coll246/378/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-feae877c-396a-4c19-b75c-0301ceaf995c",
      "cw-45d001ab-2f72-4fc0-a983-52c93ccb982b"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-03bfc82f-0ac5-44f8-8908-d3afe01ed633",
    "manifestId": "https://cdm16022.contentdm.oclc.org/iiif/info/p16022coll246/378/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-45d001ab-2f72-4fc0-a983-52c93ccb982b"
  }
}