Could not apply patch to entry: invalid patch - test failed

Hello,
i try this patch :

{
    "op": "test",
    "path": "/fields/simpleTitle",
    "value": {"fr-FR": ""}
  },
  {
    "op": "add",
    "path": "/fields/simpleTitle",
    "value": {"fr-FR": "some text"}
  }

but i get this error :

{
  "sys": {
    "type": "Error",
    "id": "UnprocessableEntity"
  },
  "message": "Could not apply patch to entry: invalid patch - test failed {\"op\":\"test\",\"path\":\"/fields/ucsg\",\"value\":{\"en-US\":\"\"}}",
  "requestId": "..."
}

thanks for help :slight_smile: