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/p16022coll246/305/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-aa50256a-9155-4656-8f36-ad8664b9ad3e",
      "cw-ddc76bc3-44f8-4806-8bc3-fd150296cee9"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-1f5e0e56-460c-48a3-8d8a-2826149253db",
    "manifestId": "https://cdm16022.contentdm.oclc.org/iiif/info/p16022coll246/305/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-ddc76bc3-44f8-4806-8bc3-fd150296cee9"
  }
}