curl -X DELETE https://api2.ecomailapp.cz/smart-delivery/rules/aB3dE5fG7h \
  -H "key: YOUR_API_KEY" \
  -H "Content-Type: application/json"

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, 'https://api2.ecomailapp.cz/smart-delivery/rules/aB3dE5fG7h');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'DELETE');
curl_setopt($ch, CURLOPT_HTTPHEADER, [
    'key: YOUR_API_KEY',
    'Content-Type: application/json',
]);
$response = curl_exec($ch);
curl_close($ch);

{
  "success": false,
  "message": "System sending policies cannot be edited or deleted."
}

{
  "success": false,
  "message": "Sending policy not found."
}

{
  "success": false,
  "message": "This sending policy cannot be deleted because it is used in campaigns or automations.",
  "data": {
    "count": 2,
    "pipelines": [
      {
        "pipeline_id": 42,
        "action_id": "4f6c2a9e-1b7d-4e3a-9c8f-2d5b6a7e8f90"
      }
    ],
    "campaigns": [
      {
        "campaign_id": 1234,
        "title": "Newsletter"
      }
    ]
  }
}