Joining meeting using MeetingSDK fails with AUTHRET_UNKNOWN

Description
I have a Windows application (.Net 4.8 / C#) that integrates with the Zoom Meeting SDK.

I am able to generate the JWT token after creating the app on the Marketplace and my application initializes the SDK successfully.

  • GetAuthServiceWrap().SDKAuth returns SDKERR_SUCCESS

However, the authentication callback (GetAuthServiceWrap().Add_CB_onAuthenticationReturn() ) does not return AUTHRET_SUCCESS, it retuns AUTHRET_UNKNOWN.

I have tried to capture the last Zoom error - but I do not find GetZoomLastError() in the C# wrapper.

I am unable to Join (or Start) a meeting.

Which Windows Meeting SDK version?
v5.16.1.22573

To Reproduce
Steps to reproduce the behavior:

  1. Initialize the SDK
    ZOOM_SDK_DOTNET_WRAP.CZoomSDKeDotNetWrap.Instance.Initialize()

  2. Wire the authentication callback:
    GetAuthServiceWrap().Add_CB_onAuthenticationReturn([callback delegate goes here])

  3. Use the Client ID and Client Secret from the app registration in the Marketplace to generate the JWT token:

            string zoomClientID = "[ client id goes here]";
            string zoomClientSecret = "[ client secret goes here]";

            int secondsSinceEpoch = (int)DateTimeOffset.Now.ToUnixTimeSeconds();
            int secondsToExpire = secondsSinceEpoch + 86400;             // default to 24 hours: cannot be more than 48 hrs.

            var payload = new Dictionary<string, object>();
            payload.Add("appKey", zoomClientID);
            payload.Add("iat", secondsSinceEpoch);
            payload.Add("exp", secondsToExpire);
            payload.Add("tokenExp", secondsToExpire);

            string jwt_value = Jwt.JsonWebToken.Encode(payload, zoomClientSecret, Jwt.JwtHashAlgorithm.HS256);




  1. Authenticate the SDK
ZOOM_SDK_DOTNET_WRAP.AuthContext param = new ZOOM_SDK_DOTNET_WRAP.AuthContext
{
     jwt_token = [ jwt token goes here ]
};
status = zoom_instance.GetAuthServiceWrap().SDKAuth(param);

*Observe that ‘status’ = SDKERR_SUCCESS

  1. Handle the authentication callback
bool result == ZOOM_SDK_DOTNET_WRAP.AuthResult.AUTHRET_SUCCESS
  • Observe that ‘result’ = AUTHRET_UNKNOWN

Context
This app is for private use only, not published in the Marketplace.
I suspect I am missing the API_User ZAK, but I’m not clear on how to get it.

When I try calling ‘get /users/{userId}/token’ using the JWT token I get back “Invalid access token”.
Which is weird as that same token just authenticated successfully.

@p3john , what is the type of Windows Application you referring to?

It has been tested to work on WPF (.net) and Windows form(.net) application.