(a)Smack returns “service-unavailable (503)” error at login()
问题 I'm trying to implement a simple jabber messenger on Android using asmack library. Here's the code: public boolean login() { if (connection != null && connection.isConnected()) { Log.i("XMPP", connection.getHost()); try { connection.login(USERNAME, PASSWORD); } catch (XMPPException e) { e.printStackTrace(); return false; } return true; } return false; } Exception I get after connection.login() (connection looks fine): service-unavailable(503) at org.jivesoftware.smack.NonSASLAuthentication