iOS AWS API Gateway : Unauthenticated access is not supported for this identity pool

//setup service config
    AWSServiceConfiguration *serviceConfiguration = [[AWSServiceConfiguration alloc] initWithRegion:CognitoIdentityUserPoolRegion credentialsProvider:nil];


    //create a pool


    AWSCognitoIdentityUserPoolConfiguration *configuration = [[AWSCognitoIdentityUserPoolConfiguration alloc] initWithClientId:CognitoIdentityUserPoolAppClientId  clientSecret:nil poolId:CognitoIdentityUserPoolId];

    [AWSCognitoIdentityUserPool registerCognitoIdentityUserPoolWithConfiguration:serviceConfiguration userPoolConfiguration:configuration forKey:@"UserPool"];

    AWSCognitoIdentityUserPool *pool = [AWSCognitoIdentityUserPool CognitoIdentityUserPoolForKey:@"UserPool"];

    pool.delegate = self;

    AWSCognitoCredentialsProvider *credentialsProvider = [[AWSCognitoCredentialsProvider alloc] initWithRegionType:CognitoIdentityUserPoolRegion
                                                                                                    identityPoolId:CognitoIdentityPoolId];

    AWSServiceConfiguration *configuration1 = [[AWSServiceConfiguration alloc] initWithRegion:CognitoIdentityUserPoolRegion
                                                                          credentialsProvider:credentialsProvider];

    [AWSServiceManager defaultServiceManager].defaultServiceConfiguration = configuration1;

Above is my code in appdelegate. I'm using sample from AWS document "CognitoYourUserPool" to login. And trying to call API using Generated SDK for iOS.

 API_Client *apiInstance = [API_Client defaultClient];
    [apiInstance setAPIKey:@"xxxxxxxxxxxxxxxxxxxxxx"];        
    [[apiInstance presetTypeGet] continueWithBlock:^id _Nullable(AWSTask * _Nonnull t) {
        NSLog(@"error: %@",t.error);
        NSLog(@"result: %@",t.result);
        return nil;
    }];

I did call the API after logged in. but it's error. I dont know why for now. Please help me. If you need more information please ask. Thank you very much.

After 2 days, I figure it out.

 AWSCognitoCredentialsProvider *credentialsProvider = [[AWSCognitoCredentialsProvider alloc] initWithRegionType:CognitoIdentityUserPoolRegion
                                                                                                    identityPoolId:CognitoIdentityPoolId identityProviderManager:pool];

Need to set identityProviderManager. Thank you very much.