Mirador viewer

SyntaxError: Unexpected token '<', "<br />
<b>"... is not valid JSON

{
  "manifest": {
    "error": "SyntaxError: Unexpected token '<', \"<br />\n<b>\"... is not valid JSON",
    "id": "https://iiif.rbge.org.uk/herb/iiif/E00032047/manifest",
    "isFetching": false
  },
  "window": {
    "collectionIndex": 0,
    "companionAreaOpen": true,
    "companionWindowIds": [
      "cw-a20331a0-f9d8-4d78-b682-73462e50f997",
      "cw-1a2e6f8b-2840-4700-9bbd-6b3d47265faa"
    ],
    "draggingEnabled": true,
    "highlightAllAnnotations": false,
    "id": "window-820ea71e-58c0-4b3c-ac66-d815b9cb9ba9",
    "manifestId": "https://iiif.rbge.org.uk/herb/iiif/E00032047/manifest",
    "maximized": false,
    "rangeId": null,
    "rotation": null,
    "selectedAnnotations": {},
    "sideBarOpen": false,
    "sideBarPanel": "info",
    "thumbnailNavigationId": "cw-1a2e6f8b-2840-4700-9bbd-6b3d47265faa"
  }
}