I'm using the Dutch prodiver Telfort on my pc. I would like to make phone calls and also answering them of course! However, as soon as I call to that phone number, I do see the phonenumber which is calling, however as soon as I click on answering, nothing happens and the phones keep ringing. Also when I want to make a phone call, it immediately says that the destination is busy, while it isn't! Does anyone the problem and hopefully the solution? Thank you in advance!