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/maps1/26465/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-663c03bc-2717-4cba-8567-70481eea9f38",
      "cw-d6af8a82-9d40-4237-8015-5d086cd95305"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-08fdd062-7335-403e-8c47-bd9d57066ca9",
    "manifestId": "https://digital.libraries.psu.edu/iiif/info/maps1/26465/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-d6af8a82-9d40-4237-8015-5d086cd95305"
  }
}