FTD API: How to clear conn?

[NicoloEreni4360]

Hello
Im trying to clear connections using FTD api /action/command passing as body a json like

{
"commandInput": "clear conn all",
"type": "Command"
}

it does not work for me...reply is

{
"error": {
"severity": "ERROR",
"key": "Validation",
"messages": [
{
"description": "This command is not supported or not recognized. Command abbreviations are not allowed.",
"code": "cliCommandNotSupported",
"location": ""
}
]
}
}

is it possible to clear connections via API? 

Thanks
Nicolo`