If a user redirects to a subscriber who has Follow-Me active, the call does not go through when the user is called. The call is rejected by the XPhone server.
By default, a central AnyDevice call forwarding number is configured to which each Follow-Me subscriber redirects to activate Follow-Me. In order for the XPhone Server to accept the call, it must recognize the Follow-Me subscriber who diverted the incoming call to the XPhone Server. This is done using the "Diversion" or "History header" in the SIP-Invite, which is sent from the PBX to the XPhone Server.
More information about this: https://www.c4b.com/en/knowledgebase/xcc/analyze-xcc-follow-me-problems.php
If a user diverts to a Follow-Me subscriber, the PBX does not signal the phone number of the Follow-Me subscriber in the "Diversion" header, but of the user who diverted to the Follow-Me subscriber.
The XPhone Server rejects the call for this reason, since it cannot find a Follow-Me device for the redirecting user. The actual Follow-Me subscriber is not signaled in the SIP Invite of the PBX, which is why the behavior of this method cannot be fixed or bypassed by C4B.
To resolve this behavior, Follow-Me must be configured using a different method.
This other method is that the Follow-Me subscribers do not redirect to a central number, but to a selected prefix followed by their own extension. This redirection to the prefix must be routed to the SIP trunk of the XPhone Connect server in the same way as the central call number. Usually, the existing entry in the PBX can be edited for this purpose.
You must make the following adjustments in XPhone Server.
1) Edit the affected SIP gateway in the administration interface under System settings > Telephony > Gateways > SIP.
2) Remove the central AnyDevice call forwarding number in the SIP gateway and deactivate the function by removing the check mark.
3) Configure the XccGatewayInPrefix in the 'Advanced Settings' of the SIP gateway. To do this, enter the desired prefix (here the prefix 99 was selected as an example)
4) Adjust the Internal number length in your dialing parameters in the administration interface under System settings > Dialing parameters. This must be adjusted in the dialing parameter of your fixed network gateway as well as the SIP gateway. The internal call number length must be at least prefix+extension (e.g. prefix+extension 99+123, the internal call number length is at least 5).
Note: If you want to keep the internal number length low, follow the steps from this article:
How can I avoid long internal number lengths with XccGatewayInPrefix?
5) Adjust the PBX to allow call forwarding to the selected prefix+extension and to route calls to the prefix+extension to the XPhone Server SIP trunk.
6) Users must now restart their XPhone Connect clients for the changes to take effect.
More details about the configuration of the XccGatewayInPrefix can be found here: https://help.c4b.com/de/xphone-connect-8/admin/#5831.htm
Follow-Me subscribers now redirect to the prefix+your own extension rather than to a central number. This redirection to the prefix+extension is set automatically by the XPhone server when Follow-Me is activated with XccGatewayInPrefix configured.
If a user now redirects to a Follow-Me subscriber, the call is correctly delivered to the AnyDevice of the Follow-Me subscriber. The reason for this is that the "Diversion" header in the SIP-Invite is no longer taken into account, but the "To" header, in which the PBX signals the correct phone number prefix+extension.