This article explains how to create a so-called debug log of the remote TAPI driver and how to provide this for analysis.
Control Panel → Phone and Modem
(At the first start a window appears in which you enter the area code without 0)
Here you go to the "Advanced" tab and select the "estos UCServer Remote TAPI Driver".
In the window that appears, select the "Info" tab and check the "Driver protocol" box.
Example screenshot: Control Panel – Phone and Modem – Remote TSP – Driver Protocol
The files are placed in the default path C:\remotetsp\.