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/p16022coll231/21/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-a54f5daf-d15e-498a-9447-f428d513f42c",
      "cw-53002250-1aeb-4def-94b9-19ee4c8e0ae1"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-1be15efb-b599-4c55-ac8d-e8d190c9eb4f",
    "manifestId": "https://cdm16022.contentdm.oclc.org/iiif/info/p16022coll231/21/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-53002250-1aeb-4def-94b9-19ee4c8e0ae1"
  }
}