Ok - so I created a brand new telerik asp.net core mvc application added a grid and then added the one line of code and it through the error as mentioned above. It seems to be related to asp.net core.
I cant upload the project because it is to big for the forum. However it should be easy for you to replicate. It took me about 1min to create the project and add the grid and one line of code.
Thanks for your help.
