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/maps1/30034/manifest.json",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-a652bfaa-9644-4992-b9a2-63987d51f28f",
      "cw-e6bcab1d-ea45-4a91-9bae-ddbd950a6206"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-5d6989c2-ba46-44e2-ab4e-40308db11b38",
    "manifestId": "https://digital.libraries.psu.edu/iiif/info/maps1/30034/manifest.json",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-e6bcab1d-ea45-4a91-9bae-ddbd950a6206"
  }
}