Mirador viewer

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

{
  "manifest": {
    "error": "SyntaxError: Unexpected token '<', \"<!DOCTYPE \"... is not valid JSON",
    "id": "/api/digital_items/150038/2/manifest.json/",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-5176919d-69a1-4abf-9954-efceea51c954",
      "cw-11c2af9f-ff02-4469-a145-0577a8cc6c49"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-44d58e69-2e66-44b1-b3bd-0cbf25fdaab4",
    "manifestId": "/api/digital_items/150038/2/manifest.json/",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "annotations",
    "thumbnailNavigationId": "cw-11c2af9f-ff02-4469-a145-0577a8cc6c49",
    "thumbnailNavigationPosition": "off",
    "loadedManifest": "/api/digital_items/150038/2/manifest.json/",
    "canvasIndex": 0
  }
}