Mirador viewer

SyntaxError: Unexpected token '<', "<!DOCTYPE "... is not valid JSON

{
  "manifest": {
    "error": "SyntaxError: Unexpected token '<', \"<!DOCTYPE \"... is not valid JSON",
    "id": "https://digital.libraries.psu.edu/iiif/info/maps1/9349/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-d0caa308-03f7-4239-b7cb-afa35bd4caa1",
      "cw-6828250f-bcfb-4b13-ab8e-ad34e93d877f"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-82f90b7c-9127-449f-bb51-7028cee0c45c",
    "manifestId": "https://digital.libraries.psu.edu/iiif/info/maps1/9349/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-6828250f-bcfb-4b13-ab8e-ad34e93d877f"
  }
}