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/maps1/30365/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-130ad202-6649-4884-a165-1b0829fcae3a",
      "cw-9eb52ef3-3004-4ae9-930d-fafbb42bddef"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-ea2617c8-b733-4cc2-a7bf-b9d41f290d25",
    "manifestId": "https://digital.libraries.psu.edu/iiif/info/maps1/30365/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-9eb52ef3-3004-4ae9-930d-fafbb42bddef"
  }
}