Failed: Webhook HTTP post request failed with exception The remote server returned an error: (400)

[vigaude]

I can't understand which is my mistake in this task, can someone help me?

I want create a bot that every day update a list of row with the correct prices for each row and change the date (only for the row with [FORNITORE]="95e4513a":

{
"Action": "Edit",
"Properties": {
"Locale": "it-IT",
"Location": "47.623098, -122.330184",
"Timezone": "Central Europe Standard Time"
},
"Rows": [
<<START: SELECT( LISTINI ACQUISTO[ID],([FORNITORE]="95e4513a"))>>
{
"ID":"<<[id]>>",
"P": "<<IF([PRODOTTO].[prezzo medio di acquisto]>0,
[PRODOTTO].[prezzo medio di acquisto]/23,[PRODOTTO].[Costo max:]/23)>>",
"DATA": "<<TODAY()>>"

},
<<END>>
]
}

When I try it doesn't work and the error is:

Failed: Webhook HTTP post request failed with exception The remote server returned an error: (400) Bad Request.

I have check online and the error can be:

1. 400 Bad Request
   a. The Application Access Key is missing.  (non possible is automatically set by appsheet )
   b. The AppId is missing. (non possible is automatically set by appsheet)
   c. The Post body contains invalid data.

so I think that the problem is "c" The Post body contains invalid data but I can't understand what is the problem.....

thanks for help