Why asterisk not properly working with android sip client?

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http://stackoverflow.com – Asterisk= Android= 2.3/4.0.3 Android Sip client=Native Android sip client/sipdemo When i call from my pc using zoiper/xlite to android (native android sip client) now i can hear audio from both sides but when i make call from android to pc (zoiper/xlite) i cannot hear anything on android. On the other hand i have tested this scenario on elastix (which also uses asterisk with no problem in audio. pc(zoiper) ip android ip asterisk server ip Sip debug when calling from android to zoiper . <--- SIP read from UDP: (HowTos)