ASIHTTPRequest每次都失败

Question

Iam使用ASIHTTPRequest POST方法从服务器获取json直到昨天我能够从服务器获取json但是从昨天晚上起我没有从serverI获取任何东西试图在模拟器中运行代码然后从服务器获取json（我的互联网现在有点慢）。我确认服务器没有变化。

这是我的日志中的错误

Error Domain=ASIHTTPRequestErrorDomain Code=1 "A connection failure occurred" UserInfo=0x170268400 {NSLocalizedDescription=A connection failure occurred, NSUnderlyingError=0x17005e4b0 "The operation couldn’t be completed. (kCFErrorDomainCFNetwork error 2.)"}

这是我获取JSON的代码

- (void)fetchData
{
    NSArray *keys = [NSArray arrayWithObjects:@"action", @"conferenceId", nil];

    NSArray *objects = [NSArray arrayWithObjects:@"query", [NSNumber numberWithInt:1], nil];

    NSDictionary *jsonDictionary = [NSDictionary dictionaryWithObjects:objects forKeys:keys];

    NSString* jsonBody = [jsonDictionary JSONRepresentation];
    NSLog(@"jsonBody%@",jsonBody);

    NSURL *url = [NSURL URLWithString:@"http://exampleurl.com/query"];

    _queryRequest = [ASIFormDataRequest requestWithURL:url];


    [_queryRequest setPostValue:jsonBody forKey:@"queryJSON"];
    NSLog(@"_queryRequest%@", [_queryRequest valueForKey:@"postData"]);
    [_queryRequest setDelegate:self];
    [_queryRequest setRequestMethod:@"POST"];
    [_queryRequest startAsynchronous];
       NSLog(@"startAsynchronous");
}


#pragma mark HTTPRequest Delegate Methods

- (void)requestStarted
{
    NSLog(@"requestStarted");
}

- (void)requestFinished:(ASIHTTPRequest *)request
{
    NSString *responseString = [request responseString];

    responseString = [responseString stringByTrimmingCharactersInSet:[NSCharacterSet newlineCharacterSet]];

    NSLog(@"Response %d ==> %@", request.responseStatusCode, [request responseString]);
    if (request == _queryRequest)
    {
        [self processQueryResponse:responseString];
    }
}
- (void) requestFailed:(ASIHTTPRequest *)request {
    NSLog(@"%@",request.error);
}

以下是_queryRequest变量的值

(
        {
        key = queryJSON;
        value = "{\"action\":\"query\",\"conferenceId\":1}";
    }
)

请帮助我，为什么它突然在设备上失败???