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/maps1/1065/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-480e77bd-5d07-414f-9914-d52ecb8a3af6",
      "cw-5b49d59c-a541-461e-b461-cd4fee5b0fe8"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-471236da-b4fd-4191-b167-9836b755a0d6",
    "manifestId": "https://digital.libraries.psu.edu/iiif/info/maps1/1065/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-5b49d59c-a541-461e-b461-cd4fee5b0fe8"
  }
}