Call forwarding and DECT terminals
If your terminal does not forward the call correctly with unexpected results (the call falls, or remains hanging, or a three-party conference is activated), the first thing to do is to deactivate support for the REFER standard (menu Toolbox – Terminals). REFER is a SIP method used during call transfer. Most DECT terminals do not support this standard.
If, on the other hand, a three-party conference is activated, it will be necessary to deactivate the conference function of the terminal, since the conference must be managed by the PBX via the GUI.