2017-09-01 12:42:24:745 MESSAGE channel [0x5597673740]: keep alive sent to [UDP://
stagingreachme.instavoice.com:5060]
2017-09-01 12:42:34:795 MESSAGE channel [0x5597673740]: keep alive sent to [UDP://
stagingreachme.instavoice.com:5060]
2017-09-01 12:42:44:845 MESSAGE channel [0x5597673740]: keep alive sent to [UDP://
stagingreachme.instavoice.com:5060]
2017-09-01 12:42:54:896 MESSAGE channel [0x5597673740]: keep alive sent to [UDP://
stagingreachme.instavoice.com:5060]
2017-09-01 12:43:04:925 MESSAGE channel [0x5597673740]: keep alive sent to [UDP://
stagingreachme.instavoice.com:5060]
2017-09-01 12:43:14:977 MESSAGE channel [0x5597673740]: keep alive sent to [UDP://
stagingreachme.instavoice.com:5060]
2017-09-01 12:43:25:005 ERROR channel [0x5597673740]: could not send UDP packet because [Operation not permitted]2017-09-01 12:43:25:010 ERROR channel [0x5597673740]: could not send [4] bytes of keep alive from [UDP://
10.102.123.99:57663] to [<sip:sip address>:5060]
2017-09-01 12:43:25:011 MESSAGE channel 0x5597673740: state ERROR
2017-09-01 12:43:25:066 MESSAGE refresher [0x55979bfc00] has channel [0x5597673740] in state [ERROR], reporting error
2017-09-01 12:43:25:066 MESSAGE Refresher[0x55979bfc00]: scheduling next timer in 500 ms for purpose [retry]
2017-09-01 12:43:25:066 MESSAGE Register refresher [503] reason [io error] for proxy[<sip:sip address>:5060]
2017-09-01 12:43:25:066 MESSAGE Refresher[0x55979bfc00]: scheduling next timer in 500 ms for purpose [retry]
2017-09-01 12:43:25:066 MESSAGE Register refresher [503] reason [io error] for proxy[<sip:sip address>:5060]
AFTER ABOVE ERROR, voipClient(using liblinphone) try to register and we keep getting error"error: Operation not permitted " for 30 or more minute before successful REGISTRATION