Why am I getting a "Cannot access a disposed object" error when trying to make a RingOut call via RingCentral SDK?

Question

I am trying to make make a RingOut call with RingCentral using their RingCentral SDK. I am basically following their tutorial found here:

https://developers.ringcentral.com/guide/voice/quick-start/c-sharp

Other than the fact that I'm trying to do this in an MVC web app and not in a console app my code basically looks identical to theirs:

    public async Task<JsonResult> Call(string number)
    {
        var rc = new RestClient(RingCentralCredentials.ClientId, RingCentralCredentials.ClientSecret, false);
        var tokenInfo = await rc.Authorize(RingCentralCredentials.Username, RingCentralCredentials.Extension, RingCentralCredentials.Password);
        // The above line throws the exception.
        var parameters = new MakeRingOutRequest();
        parameters.from = new MakeRingOutCallerInfoRequestFrom { phoneNumber = RingCentralCredentials.Username };
        parameters.to = new MakeRingOutCallerInfoRequestTo { phoneNumber = number };
        parameters.playPrompt = false;
        var resp = await rc.Restapi().Account().Extension().RingOut().Post(parameters);
        return Json(resp.status, JsonRequestBehavior.AllowGet);
    }

yet for some reason when I run this code I get the following error when the execution gets to the Authorization line:

Cannot access a disposed object.
Object name: 'System.Net.Http.FormUrlEncodedContent'.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.ObjectDisposedException: Cannot access a disposed object.
Object name: 'System.Net.Http.FormUrlEncodedContent'.

Does anyone have any advice with regards to this? The SDK version I'm using is 1.2.1:

https://www.nuget.org/packages/RingCentral.Net/1.2.1

I think it might be a [dup of this one](https://stackoverflow.com/q/4573526/1270789) - you have a `RingCentralCredentials.Close()` or similar somewhere before you call this code? — Ken Y-N, Jul 16 '19 at 04:41
@KenY-N If you are referring to my RingCentralCredentials that I'm using above, it's a static class that just contains static properties for credentials - basically hardcoded values ClientId, ClientSecret, etc. There is no Close() method on that class. I don't have any other code related to RingCentral outside of what I included in my question. — Marko, Jul 16 '19 at 05:56

Tyler Liu · Answer 1 · 2019-07-18T16:13:40.893

The original app in the tutorial is a console app. Can you also reproduce the issue with a console app? Or is this a web app only issue? I saw you opened a RingCentral support case. I will reply you in that support case. Once we found the root case I will post update here.

Update: I've tried the sample code provided by Marko and I think I've found the root cause. The RingCentral app being used doesn't allow password flow while we tried to authorize by password. More information about this issue: https://forums.developers.ringcentral.com/questions/452/http-400-unauthorized-for-this-grant-type.html

Why am I getting a "Cannot access a disposed object" error when trying to make a RingOut call via RingCentral SDK?

1 Answers1