CRVStompClient with GCDAsyncSocket

I have implemented CRVStompClient in addition of GCDAsyncSocket by robbiehanson. When the GCDAsyncSocketDelegate method - (void)socket:(GCDAsyncSocket *)sock didConnectToHost:(NSString *)host port:(UInt16)portis called, the app crashs in the following line.

CFTypeRef ref = CFReadStreamCopyProperty(readStream, kCFStreamPropertySSLPeerCertificates);

In this Line, Xcode says readStream is 0x0.

Does anyone have/had the same issue? I would like to solve this quickly. In case someone would like to read the hole code, don't hesitate to ask for it.

I've uploaded an Demo Version of my Code on Github.
https://github.com/DanielBocksteger/objc-stomp

Best regards,
Daniel