Matrix: IVC dropped lines
If your IVC connection to LQ and IP directs / trunks drop and stopped working for some reason, normally a timeout is the reason.
You can reset the IP data link by selecting the IPA (IVC mode) or IVC-32 card in the IP panels page and select restart blocked connections buttons.
The Restart Blocked Connections button at the bottom of the Diagnostics screen is used to
restart a call initiated using IP directs and trunks.
also see FAQ : How to Re-Start IVC Card Trunk / Direct Connections After Network Outage