环信3.x 群主同意入群报错errorUser has no right for this operation.

有大神给解决一下，在线等 

- (void)didReceiveJoinGroupApplication:(EMGroup *)aGroup
                             applicant:(NSString *)aApplicant
                                reason:(NSString *)aReason{
    
    EMError *error = [[EMClient sharedClient].groupManager acceptJoinApplication:aGroup.groupId  applicant:aApplicant];
    if (!error) {
        NSLog(@"已同意入群");
    }else{
        NSLog(@"error%@",error.errorDescription);
        //errorUser has no right for this operation.为什么报这个错，同意不了
    }
}