we make configuration for our SIP line with this steps :
1- we go to SIP Trunk
2- add SIP Trunk
3- select country we select Generic
4- select provider in your country we select Generic SIP Trunk
5- Main Trunk No we add our main number without (area code and country code)
for Trunk Details steps we add the IP for out SIP Line in (Gateway Hostname / Outbound Proxy )
for Authentication type we select don not require - IP Based