SIP T20P call dropped after 3 sec's

[FlorinT]

Hi all,


I'm trying to configure a T20P to be used as a hotline phone (it should call only customers support number). I've managed to restrict it to call only a number by setting (.) as a prefix in Dial Plan + the phone number (on the "Replace" column)

My problem is that any outgoing call is dropped when answered, after 3 sec.
Any ideea why it's dropping the calls?

Thx,
Florin