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/p16022coll246/339/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-54b57c17-62d6-4219-805a-a91be8646f4e",
      "cw-efd02585-c4cc-42c6-81e7-51bf984b5afd"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-3df5ed7f-98f3-44d6-9f42-e707c287faa0",
    "manifestId": "https://cdm16022.contentdm.oclc.org/iiif/info/p16022coll246/339/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-efd02585-c4cc-42c6-81e7-51bf984b5afd"
  }
}