[Freeswitch-users] Phone lines ring busy after awhile

Hello. I have an installation of FreeSwitch runnnig, and I wrote a Python script to answer an inbound call and play an IVR. It works fine for awhile, but eventually it stops answering the phone line and the phone rings busy. When I look in the FreeSwitch logs I don't see anything unusual. But I don't think it's a problem with the VOIP phone service because when I restart FreeSwitch the problem goes away. Any ideas?