curl --request POST \
  --url https://api.hubapi.com/cms/blogs/2026-03/posts/multi-language/update-languages \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: */*' \
  --data '
{
  "languages": {},
  "primaryId": "<string>"
}
'

{
  "message": "Invalid input (details will vary based on the error)",
  "correlationId": "aeb5f871-7f07-4993-9211-075dc63e7cbf",
  "category": "VALIDATION_ERROR",
  "links": {
    "knowledge-base": "https://www.hubspot.com/products/service/knowledge-base"
  }
}