Mirador viewer

TypeError: Failed to fetch

{
  "manifest": {
    "error": "TypeError: Failed to fetch",
    "id": "https://digital.libraries.psu.edu/iiif/info/maps1/20748/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-34e2d752-5983-43bf-aeac-415029b384ea",
      "cw-7fa92cc8-79c9-4e16-9f37-729ff3279e3a"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-8c25fd0b-47eb-426c-be77-0079242395c3",
    "manifestId": "https://digital.libraries.psu.edu/iiif/info/maps1/20748/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-7fa92cc8-79c9-4e16-9f37-729ff3279e3a"
  }
}