Incoming calls, delay to hangup FXO analog interfaces!

Hi, i have a OpenVox TDM400P and I am able to get calls to my PBX normally, but if a client call to my office and once the line is answered by the IVR, the client hangup his phone, the asterisk take something in range like 10-12 seconds to hangup the line.
i have this in zapata.conf config


I want to know if exist a file to edit to fix this problem.