I have  6 sip members in my sales  queue, when I received PSTN call on the same queue and if any one is in hold than that sip phone hangs. So to get this phone in operation I have to reboot this phone..

extensions.conf
============
exten => 162728,1,Queue(sales|tT)
exten => 162728,2,Hangup


queues.conf
===========
[sales]
strategy = ringall
timeout = 0
retry = 10
wrapuptime=15
maxlen = 0
announce-frequency = 90
announce-holdtime = once
queue-thankyou = queue-thankyou
member => SIP/mark
member => SIP/steve
member => SIP/solo
member => SIP/botham
member => SIP/flintof
member => SIP/spanser