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/p16022coll624/254/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-dc8aa81a-9eff-4eef-af76-3ecd87386dd8",
      "cw-84b7c289-0bcd-464f-baba-7015c0d1d8c3"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-b92e17df-628c-42d5-9b62-a6ef307c41ce",
    "manifestId": "https://cdm16022.contentdm.oclc.org/iiif/info/p16022coll624/254/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-84b7c289-0bcd-464f-baba-7015c0d1d8c3"
  }
}