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/mgs/695/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-100c1492-d422-4db7-af57-0db073d8dfc6",
      "cw-2133ea96-6c82-4c9d-abd8-06e6f56c019d"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-6c41cd8c-6920-45b3-90d3-aacbce4ebead",
    "manifestId": "https://cdm16022.contentdm.oclc.org/iiif/info/mgs/695/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-2133ea96-6c82-4c9d-abd8-06e6f56c019d"
  }
}