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/p16022coll624/303/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-0202152a-c28d-4b77-82a6-7aff6ddf3a90",
      "cw-20b336c8-9121-4772-8c55-0c2edcb1e36f"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-8b7df778-49a3-4f13-a74a-4def7ef13118",
    "manifestId": "https://cdm16022.contentdm.oclc.org/iiif/info/p16022coll624/303/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-20b336c8-9121-4772-8c55-0c2edcb1e36f"
  }
}