--- title: "Error 003 SIP Registration Failure" slug: "error-003-sip-registration-failure" updated: 2026-05-11T10:52:09Z published: 2026-05-21T21:28:00Z canonical: "help.8x8.com/error-003-sip-registration-failure" --- > ## Documentation Index > Fetch the complete documentation index at: https://help.8x8.com/llms.txt > Use this file to discover all available pages before exploring further. # Error 003 SIP Registration Failure ## Symptom Your Panasonic KX-TGP600 DECT phone is receiving the following error, *Error 003: Not registered.* ## Applies To - Panasonic KX-TGP600 DECT Phones ## Resolution > [!NOTE] > Note: > > This product has reached end of life. [Create a Case with 8x8 Support](/support/docs/create-a-case-with-8x8-support). ## Cause This error may result from a bad configuration, failed handset pairing, a device requiring pairing, or a non-activated or offline base unit.