- My polycom phone is indicating the line is not available (red mark instead of green) on the VVX400 or higher.
- Yet the phone is showing as registered in PISTON.
- The PISTON registration source port is below 1024.
- Assuming there is network connectivity to Voxter's hosted PBX servers, then the cause of this behaviour is related to the firewall/router having SIP ALG enabled. Please login to the router and disable SIP ALG. Rebooting the affected phone may be required.