Мірадор - viewer

SyntaxError: Unexpected token '<', "<!DOCTYPE "... is not valid JSON

{
  "manifest": {
    "error": "SyntaxError: Unexpected token '<', \"<!DOCTYPE \"... is not valid JSON",
    "id": "/api/digital_items/439/2/manifest.json/",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-295587fa-9975-4f5a-b423-e2b9ea412676",
      "cw-5704c5be-6b5b-440c-ac92-6e0cbfa7cb91"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-e3c2e840-e52c-4bb1-9417-7ae254f65af3",
    "manifestId": "/api/digital_items/439/2/manifest.json/",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "annotations",
    "thumbnailNavigationId": "cw-5704c5be-6b5b-440c-ac92-6e0cbfa7cb91",
    "thumbnailNavigationPosition": "off",
    "loadedManifest": "/api/digital_items/439/2/manifest.json/",
    "canvasIndex": 0
  }
}