Concat text to form an email with multiple records

I want to concat multiple records into one text field to form a email with multiple records, for example list all products from an Order.

I've added a Read data (named ReadDataUserTask5) to my process and the added Script element like this:

var list = Get> ("ReadDataUserTask5.ResultCompositeObjectList");

var sb = new StringBuilder(); 
foreach (ICompositeObject item in list) 
{
  if (item.TryGetValue("Quantity", out decimal value)) {
    sb.Append(value.ToString()).Append("x\t");
  }

  if (item.TryGetValue("Name", out string valueName))
  {
    sb.Append(valueName).Append("\n");
  }
}

Set("ListaProducta", sb.ToString());
return true;

but my process is stuck on this script element and never finishes. What am I missing here?

I've tried adding "ListaProducta" as an process parameter but that didnt help