Client is not permitted to perform this action STTwitter Error

Question

I am using STTWitter for login using twitter. I have created an app.

When I try to call login method I am getting this error:

 Error Domain=STTwitterTwitterErrorDomain Code=87 "
 Client is not permitted to perform this action"

I am using this method to login:

STTwitterAPI *twitter = [STTwitterAPI twitterAPIWithOAuthConsumerKey:@"sqsamplekeyzWcESlRq3h"
                                                      consumerSecret:@"pgs0nD4qconsumeersecretkeyjOOzLk83obgw2s341WHlQ"
                                                            username:@"username"
                                                            password:@"password"];



[twitter verifyCredentialsWithUserSuccessBlock:^(NSString *username, NSString *userID) {

    NSLog(@"YES");
    // ...
} errorBlock:^(NSError *error) {
    NSLog(@"%@",error);
    // ...
}];