Thank you for your response. My register is set to expire after 180 seconds. I am already in touch with voip.ms support. Phone not ringing is very rare and does not occur often. However, I am very frustrated about other issues such as phone disconnecting the moment I pick it up. There are other minor issues as well such as 1 second silences during calls and perpetual sounds every few seconds during calls. It sounds as though a button has been pressed but it does not have a beep sound to it. I have checked my DTMF and tried mango's suggestions on his blog and it did not work. I am also experiencing huge packet loss on some calls. Hence why I think this is a problem with my router and not necessarily voip.ms. I will open up a thread here if voip.ms support cannot provide me with a feasible solution. Thank you once again for your response.