Cannot verify access_token to PassportJS in iOS Facebook SDK

I am trying to use Facebook iOS sdk with PassportJS (sever is NodeJS) I sucessfully managed to log in with Facebook on my iOS app. The next thing I do is hand over the access token to the server and verify from there. Unfortunately it does not work at all.

The weird part is that for my website it works fine. I just use the callback url to post the token to the server.

So in code what happens after facebook login (which works)

/*
 * Callback for session changes.
 */
- (void)sessionStateChanged:(FBSession *)session
                      state:(FBSessionState) state
                      error:(NSError *)error
{
    switch (state) {
        case FBSessionStateOpen:
            if (!error) {
                // We have a valid session
                NSString *token = session.accessTokenData.accessToken;
                NSLog(@"User session found: %@", token);
                [[NSNotificationCenter defaultCenter] postNotificationName:nGotFacebookSession object:nil userInfo:@{
                    @"token": token
                }];
            }
            break;
        case FBSessionStateClosed:
        case FBSessionStateClosedLoginFailed:
            [FBSession.activeSession closeAndClearTokenInformation];
            break;
        default:
            break;
    }

    [[NSNotificationCenter defaultCenter]
     postNotificationName:FBSessionStateChangedNotification
     object:session];

    if (error) {
        UIAlertView *alertView = [[UIAlertView alloc]
                                  initWithTitle:@"Error"
                                  message:error.localizedDescription
                                  delegate:nil
                                  cancelButtonTitle:@"OK"
                                  otherButtonTitles:nil];
        [alertView show];
    }
}

Then, in the login controller the notification gets received:

- (void) facebookLogin: (NSNotification*) notification
{
    [MBProgressHUD showHUDAddedTo:self.view animated:YES];
    NSString *token = [notification.userInfo objectForKey:@"token"];
    [[CBApi sharedAPI] get:@"api/auth/facebook/callback" andParams:@{
        @"code": token
    } andCallback:^(NSDictionary *json) {
        [MBProgressHUD hideHUDForView:self.view animated:YES];
        if ([json objectForKey:kError]) {
            Alert(@"Error", @"Login details failed");
        } else {
            User *u = [User createEntity];
            u.email = self.emailField.text;
            [self dismissViewControllerAnimated:YES completion:nil];
        }
    }];
}

And then I get this error back from the server (copypasted from console):

failed to obtain access token (status: 400 data: {
    "error": {
        "message": "Invalid verification code format.",
        "type": "OAuthException",
        "code": 100
    }
})

Like I said, it fully works when using the web site for login, no problem, it's just that it does not accept iOS native generated access tokens. I have never done fb login like this before. If you could help me that would be really great, thanks anyway!