If you have port forwarding or DMZ to your OBi100 in your router, remove this unless things won't work any other way. Using port forwarding or DMZ is a security risk.
Also, you should set the following:
Voice Services >> SPx Service:
X_UserAgentPort: 59651
The above number is a random number; you can use any valid UDP port number.
X_InboundCallRoute: {>('Insert your AuthUserName here'):ph}