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/p16022coll246/421/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-a10d6d48-ae8b-46cf-94d5-7ea453635c5a",
      "cw-fba1f7f7-d473-4fa7-b323-b558ed73ad41"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-bdc3163f-e9a0-4434-a878-c9e10f27afe7",
    "manifestId": "https://cdm16022.contentdm.oclc.org/iiif/info/p16022coll246/421/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-fba1f7f7-d473-4fa7-b323-b558ed73ad41"
  }
}