Time to time some calls disconnection

Hi,

Recently we are experiencing lots of call disconnections in our system. it happens specially for incoming calls. as an example some calls are getting disconnect when caller is listing to the IVR announcements and some calls are getting disconnected when call conversation is going on.

But couldn’t find any problem on the system. Will someone be able to help me on that?

Freepbx ver. 2.8 Asterisk (Ver. 1.4.25.1)

the file is /etc/asterisk/chan_dahdi.conf

Many Thanks for the Comments but couldn’t find any file named “chan_dahdi.conf” etc folder or anywhere in the system. I’m new to the asterisk and will be able to advise me in details

Kind Regards,

check callprogress=no in chan_dahdi.conf.