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/p16022coll246/421/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-35deca5e-1f77-4340-9be8-7442cb05cc3e",
      "cw-f04b7c32-c8e9-46a8-ae3f-6750f8db0033"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-9765f38d-40bf-4ad8-813b-2021ea26da32",
    "manifestId": "https://cdm16022.contentdm.oclc.org/iiif/info/p16022coll246/421/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-f04b7c32-c8e9-46a8-ae3f-6750f8db0033"
  }
}