A dataset is defined as either a pattern or a list, but contains no values.

How to fix

Ensure that you have supplied values for the dataset using the values attribute.

Problem example:

{
  "datasets": [
    {
      "name": "CustomNames",
      "type": "List"
      // Missing "values" property
    }
  ]
}

Ensure that you have supplied values for the dataset using the values attribute:

List dataset:

{
  "datasets": [
    {
      "name": "CustomNames",
      "type": "List",
      "values": ["Alice", "Bob", "Charlie", "Diana"]    // Added values array
    }
  ]
}

Pattern dataset:

{
  "datasets": [
    {
      "name": "PhoneNumbers",
      "type": "Pattern",
      "values": ["(###) ###-####", "###-###-####"]     // Added pattern values
    }
  ]
}