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/p16022coll231/23/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-2f1b329c-a240-48a3-ba4b-b167d600b010",
      "cw-68a5cac1-4ea5-4f05-aafe-0ac0825c1022"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-d4a5c1ee-711b-4065-8313-d5824747b149",
    "manifestId": "https://cdm16022.contentdm.oclc.org/iiif/info/p16022coll231/23/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-68a5cac1-4ea5-4f05-aafe-0ac0825c1022"
  }
}