Polycom Phone Shows 'SIP URI Disabled'

← Troubleshooting

When a Polycom phone displays “SIP URI Disabled” on screen, outbound calls fail immediately and inbound calls route directly to voicemail without ringing the phone. This message indicates the phone has lost its registration with SIPSTACK’s servers.

Causes

The two most common causes are:

1. Internet connectivity loss — The phone cannot reach SIPSTACK’s SIP proxy to maintain its registration
2. Firmware incompatibility — An outdated or corrupted firmware version is preventing successful SIP registration

Step 1: Check Internet Connectivity

Before contacting support, confirm that your internet connection is working:

1. Open a browser on a computer connected to the same network as the phone.
2. Navigate to any website (e.g., google.com).

If the website loads, internet is working and the issue is likely firmware-related — continue to Step 2.

If the website does not load, your internet connection is down. Contact your internet service provider (ISP) to restore connectivity. Once internet is restored, the phone should automatically re-register with SIPSTACK and the “SIP URI Disabled” message should clear within 1–2 minutes.

Step 2: Request a Firmware Update

If internet is confirmed working but the phone still shows “SIP URI Disabled”:

1. Note the phone’s MAC address (printed on the label on the bottom of the phone).
2. Contact SIPSTACK support and report the “SIP URI Disabled” error along with the MAC address.
3. SIPSTACK support will push the latest firmware to your phone remotely.
4. The phone reboots, installs the update, and re-registers automatically.

You will receive a confirmation email when the phone is successfully reconnected.

Note: Do not attempt to manually update Polycom firmware on phones provisioned through SIPSTACK. The SIPSTACK provisioning server manages firmware versions to ensure compatibility.