SIP-T20P: Register Failedand and no Call

[Yealink_Daniel]

Dear Sylvio,

About your scene, if you want the other phones which in other cities of your company register in your PBX and be able to communicate each other, I suggest you use our OpenVPN function.

About how to install the OpenVPN Server and how to configure this feature on IP phone, please refer the guide below.
Link:OpenVPN_Feature_on_Yealink_IP_Phones

About STUN, please refer these steps to configure the parameters in your phones:
To configure NAT traversal and STUN server via web user interface:
1. Click on Account->Register.
2. Select the desired account from the pull-down list of Account.
3. Select STUN from the pull-down list of NAT.
4. Enter the IP address or the domain name of the STUN server in the STUN Server
field.
   
5. Click Confirm to accept the change.

For more information, please refer page 418 of the Administrator Guide.
Link: Yealink_SIP-T2xP_IP_Phones_Administrator_Guide_V73_40

About how to build a STUN server, could you please contact your server provider or administrator for help ?
Because it’s build in your local and provide by your server provider or administrator.

Thank you.

Best Regards
Daniel