Hi guys!

I found that the some of the incoming call will hangup with case: WRONG_CALL_STATE,but else will be ok.After a hour,almost every incoming call will be hangup with the same cause.Then I will restart the freeswitch,it will server like before:some call will be hangup with the cause...

28e10f2e-c851-11e3-a146-85a8fadad1b0 2014-04-20 14:01:15.498169 [WARNING] switch_core_state_machine.c:567 28e10f2e-c851-11e3-a146-85a8fadad1b0 sofia/internal/123456@sipsj.236.cn Abandoned
28e10f2e-c851-11e3-a146-85a8fadad1b0 2014-04-20 14:01:15.498169 [NOTICE] switch_core_state_machine.c:570 Hangup sofia/internal/123456@sipsj.236.cn [CS_NEW] [WRONG_CALL_STATE]

What does Wrong call state mean and what can I do to fix this issue? 

Everything else is working. I can make outgoing calls and call other 
extensions. 

Thanks in advance.