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/p16022coll624/487/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-7a677e9f-99ee-454a-9cc1-166cb5267d19",
      "cw-10713364-9815-4772-b836-2c7ac30f21cf"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-60c58681-c297-4f5b-a07c-3113c096f138",
    "manifestId": "https://cdm16022.contentdm.oclc.org/iiif/info/p16022coll624/487/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-10713364-9815-4772-b836-2c7ac30f21cf"
  }
}