INVALID_OAUTHTOKEN using Self Client Access Token (Android)

Hi,

I using the Zoho Android Demo app to try to evaluate Zoho Assist. https://github.com/zoho/Assist-Customer-Android-SDK-Demo

I am successfully able to get an access token by POSTing the generated code from Self Client via POSTMAN.

scope = ZohoAssist.sessionapi.ALL

{
    "access_token": "1009962",
    "refresh_token": "10068c6efc5",
    "scope": "ZohoAssist.sessionapi.ALL",
    "api_domain": "https://www.zohoapis.com",
    "token_type": "Bearer",
    "expires_in": 3600
}

I use the access token along with the session id in demo application but it is returning a 400 response INVALID_OAUTHTOKEN.

Any idea why this would be happening? I confirmed that the correct access token is being used in onSessionStart.

I am aware the token expires after an hour.

Thanks