"'Newtonsoft.Json.Linq.JArray' does not contain a definition for" on list of nodes

Questions
1

Im using the U7 grid data type package to do some repeated content. I need to sort these items and then take 1.

BUT, i get the following error when trying to sort:

'Newtonsoft.Json.Linq.JArray' does not contain a definition for 'OrderBy'

My code is as follows

@{
var afholdelser	= CurrentPage.afholdelser.OrderBy("afholdelsdato");	
foreach (var afholdelse in afholdelser) {
	<p>do stuff</p>
}}

What am i doing wrong?

This is a companion discussion topic for the original entry at https://our.umbraco.com/forum/72831-newtonsoftjsonlinqjarray-does-not-contain-a-definition-for-on-list-of-nodes