I've been struggling with this for a couple days now. I'm trying to make calls to Google Calendar using authentication via Android's `AccountManager`. I retrieve an auth token using the usual method:

```
AccountManager manager = AccountManager.get(this);
String authToken = manager.getAuthToken(account, AUTH_TOKEN_TYPE, true, null, null).getResult().getString(AccountManager.KEY_AUTHTOKEN);

```

And then, with that token, I create a `Calendar` instance like this:

```
HttpTransport transport = AndroidHttp.newCompatibleTransport();
JacksonFactory jsonFactory = new JacksonFactory();
GoogleAccessProtectedResource accessProtectedResource = new GoogleAccessProtectedResource(accessToken);
Calendar calendar = Calendar.builder(transport, jsonFactory).setApplicationName("MyApp/1.0").setJsonHttpRequestInitializer(new JsonHttpRequestInitializer() {
    @Override
    public void initialize(JsonHttpRequest request) {
        CalendarRequest calendarRequest = (CalendarRequest) request;
        calendarRequest.setKey(API_KEY);
    }
}).setHttpRequestInitializer(accessProtectedResource).build();

```

However, when I make API calls using this, I receive the `401 Unauthorized` error seen below. Note that I have included code to invalidate expired auth tokens, so I don't believe that's the problem here.

```
com.google.api.client.googleapis.json.GoogleJsonResponseException: 401 Unauthorized
{
    "code" : 401,
    "errors" : [ {
        "domain" : "global",
        "location" : "Authorization",
        "locationType" : "header",
        "message" : "Invalid Credentials",
        "reason" : "authError"
    } ],
    "message" : "Invalid Credentials"
}

```

Any thoughts on what I might be doing wrong?