Create a new item in a list shows exception. Example from documentation.

Question

Hello,

There is an example from Graph REST API v1.0:

// Code snippets are only available for the latest version. Current version is 5.x

var graphClient = new GraphServiceClient(requestAdapter);

var requestBody = new ListItem
{
	Fields = new FieldValueSet
	{
		AdditionalData = new Dictionary<string, object>
		{
			{
				"Title" , "Widget"
			},
			{
				"Color" , "Purple"
			},
			{
				"Weight" , 32
			},
		},
	},
};
var result = await graphClient.Sites["{site-id}"].Lists["{list-id}"].Items.PostAsync(requestBody);

You can find this example here:

https://learn.microsoft.com/en-us/graph/api/listitem-create?view=graph-rest-1.0&tabs=csharp

The exception shows follow message:

What is root cause here?