下面是我在研究asmack4.0出现的异常
06-17 12:02:56.924: W/System.err(10622): org.jivesoftware.smack.SmackException$ConnectionException
06-17 12:02:56.924: W/System.err(10622): at org.jivesoftware.smack.tcp.XMPPTCPConnection.connectUsingConfiguration(XMPPTCPC onnection.java:431)
06-17 12:02:56.940: W/System.err(10622): at org.jivesoftware.smack.tcp.XMPPTCPConnection.connectInternal(XMPPTCPConnection. java:799)
06-17 12:02:56.940: W/System.err(10622): at org.jivesoftware.smack.XMPPConnection.connect(XMPPConnection.java:391)
06-17 12:02:56.940: W/System.err(10622): at com.example.testchat.MainActivity.test(MainActivity.java:121)
06-17 12:02:56.940: W/System.err(10622): at com.example.testchat.MainActivity.access$0(MainActivity.java:56)
06-17 12:02:56.940: W/System.err(10622): at com.example.testchat.MainActivity$1.run(MainActivity.java:34)
06-17 12:02:56.940: W/System.err(10622): at java.lang.Thread.run(Thread.java:856)
找了各种办法也没能解决，最后无意中发现了这个
connectionConfig = new ConnectionConfiguration(
loginConfig.getXmppHost(), loginConfig.getXmppPort(),
loginConfig.getXmppServiceName());
connectionConfig.setSecurityMode(SecurityMode.enabled);
安全模式，对没错，就是安全模式导致认证失败于是我把它改为了disabled，问题解决了
aSmack连接服务器异常smack.SmackException$ ConnectionException thrown by XMPPConnection.connect();
原文：http://blog.csdn.net/hellohhj/article/details/40736543