无法在iOS中使用XMPP实现转换套接字以进行文件传输

Question

我正在使用下面的代码创建转Socket，但每次进入turnSocketDidFail方法，所以代码中的错误，请帮帮我。

XMPPJID *JID = [XMPPJID jidWithString:@"9107@test.com/110s-Mac-mini"];

[TURNSocket setProxyCandidates:[NSArray arrayWithObjects:JID.domain, nil]];
TURNSocket *socket = [[TURNSocket alloc] initWithStream:[[NDAppDelegate shareAppDelegateInstance] xmppStream] toJID:JID];
[socket startWithDelegate:self delegateQueue:dispatch_get_main_queue()];


- (void)turnSocket:(TURNSocket *)sender didSucceed:(GCDAsyncSocket *)socket {

    NSLog(@"TURN Connection succeeded!");


}

- (void)turnSocketDidFail:(TURNSocket *)sender {

    NSLog(@"TURN Connection failed!");


}