Update Based on change in OP

As per your latest edit in the question, you have an array of MyArray. You should hence deserialize using a collection of MyArray.

For example,

 var myDeserializedClass1 = JsonConvert.DeserializeObject<MyArray[]>(rawJson); 
// OR
 var myDeserializedClass1 = JsonConvert.DeserializeObject<IEnumerable<MyArray>>(rawJson); 

Based on Original Question before the Edit

You are attempting to deserialize using wrong object type (Root), which is why it fails to do so, and returns a null value.

Your Json contains a single instance of MyArray and not an instance of Root. You need to deserialize using

var myDeserializedClass1 = JsonConvert.DeserializeObject<MyArray>(rawJson); 

That would provide you the desired result.