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

{
  "manifest": {
    "error": "SyntaxError: Unexpected token '<', \"<!DOCTYPE \"... is not valid JSON",
    "id": "https://collections.ubcic.bc.ca/iiif/2/107467/manifest",
    "isFetching": false
  },
  "window": {
    "autoScrollAnnotationList": true,
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-a0104b40-cf2c-4940-b034-3a68fa571005",
      "cw-1b2f09c9-f444-4ce8-9cae-9e6e6070f29f"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-24ff1b4b-6061-4107-81bd-35a4a9670fc7",
    "manifestId": "https://collections.ubcic.bc.ca/iiif/2/107467/manifest",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "annotations",
    "thumbnailNavigationId": "cw-1b2f09c9-f444-4ce8-9cae-9e6e6070f29f",
    "loadedManifest": "https://collections.ubcic.bc.ca/iiif/2/107467/manifest"
  }
}