For one of our application, I am trying to get Extensions for an event using the following code in C#:

```
var result = graphServiceClient.User[userid].Calendar.Events[eventid].Extensions.Request().GetAsync().Result;

```

However, I am getting following exception:

> 
> Code: ErrorInvalidRequest
> Message: The OData request is not supported.
> ClientRequestId: f7a44c2f-ca79-4f79-9726-2cdc98d87e00
> 
> 
> 

I found the above code in few of the questions posted on stackoverflow.

We need to add and get opentype extensions by any means. Can somebody please help?