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/1075/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-3d78062a-00f3-434b-938e-4260bcfb2660",
      "cw-a57c3a7f-af4a-4e24-b6c7-c362f01900a3"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-04a77fce-4def-4f45-9fcb-c3cd7021bcfd",
    "manifestId": "https://cdm16022.contentdm.oclc.org/iiif/info/mgs/1075/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-a57c3a7f-af4a-4e24-b6c7-c362f01900a3"
  }
}