Zap channels not being re-used

Good morning all,

I’ve recently setup my first Asterisk box. Let me start by saying that the help in these forums has proved invaluable.

The server itself is outfitted with a single TE110P PRI card. I’ve got a number of SIP phones making outbound calls through the PRI to the PSTN. At first glance, everything looked good, and working as intended.

However, I’m finding that once a Zap channel is used, it is not being released properly. Calls hangup OK, and scans of the PRI itself show the correct number of available channels, but once I’ve made 23 total calls, Asterisk cannot re-use any of the Zap channels to get a line. I’ve tried changing the sequence from ascending (Zap/g1) to descending (Zap/G1) and even random (Zap/r1, Zap/R1) but no luck.

Any thoughts?