[Freeswitch-users] Call hanging up after 30 minutes (exactly)

Hello, I have problems with calls being hung up after 30 minutes. I do not know if the problem is with FreeSWITCH or my sip provider. I've got a log here: http://pastebin.freeswitch.org/11962 Can you please point me in the right direction? Also, why is a second invite sent after 15 minutes? Regards, Jonas