Incoming calls are being dropped

I have about 3-4 calls per day (maybe 10% of our calls) that drop right as I pick them up. They are usually local numbers. I can’t find out why they are dropping, the only warnings I get in my log are:

WARNING[8527][C-00003960] func_channel.c: Unknown or unavailable item requested: 'reversecharge'
WARNING[8527][C-00003960] app_dial.c: Unable to create channel of type 'SIP' (cause 20 - Subscriber absent)

We do receive other calls from random numbers that drop or are telemarketing. So I’m wondering if this is a telemarketer or something else that is just masking their number to be local or if this is a client trying to reach us. Any ideas what is causing this?

Click for full log

http://forums.asterisk.org/viewtopic.php?f=1&t=86949 provides a lot of good information about this issue. If you wouldn’t mind starting there, that would be super. If you are still having problems after, let us know.

Thanks for the link, but that didn’t help much with my problem. On that link it seemed it was an RTP issue. My doesn’t seem to have that issue.

Any other ideas?

You are seeing cause 20 - the post provides good detail on what the problem is and ways to fix it.

If you have a better idea, let us know.