Unified Communications Manager 7.x: IP Phone Error Message - Registration Rejected: Error DBConfig

Introduction

This document discusses and solves the Registration Rejected: Error DBConfig error message. You might receive this error message when the IP phone auto-registers to the Cisco Unified Communications Manager (CM).

Prerequisites

Requirements

Cisco recommends that you have knowledge of Cisco Unified CM 7.x and Cisco IP Phones.

Components Used

The information in this document is based on these software and hardware versions:

• Cisco Unified CM 7.x

• Cisco 7900 Series IP Phones

Conventions

Refer to Cisco Technical Tips Conventions for more information on document conventions.

Auto-registration

Auto-registration automatically assigns directory numbers to new devices as they connect to the IP telephony network. Use Auto-registration if you want Cisco Unified CM to automatically assign directory numbers to new phones when you plug these phones in to your network.

Problem

Auto-registration fails and shows the error message Registration Rejected: Error DBConfig on the telephone screen as shown here:

Enable Auto-registration

Perform these steps in order to resolve the issue:

1. On the Cisco Unified CM Administration page, navigate to System > Cisco Unified CM.

2. Click the IP address of the Cisco Unified CM to which you want to enable Auto-registration. A new window will appear:

   

3. Uncheck the check box Auto-registration Disabled on this Cisco Unified Communications Manager in order to enable Auto-registration.

4. Choose the respective Cisco Unified CM group, normally the Default, and verify that Auto-registration Cisco Unified CM group is checked.

   1. On the Cisco Unified CM Administration page, navigate to System > Cisco Unified CM Group.

   2. Click Find. One Cisco Unified CM group which is listed as Default will appear. When you click it, you will find this page:

      

   3. Make sure the Auto-registration Cisco Unified Communications Manager Group check box is checked.

Delete Unused Directory Numbers

If the issue persists even after ensuring that Auto-registration is enabled for both the Cisco Unified CM Group and the server, you need to go to the route plan report of the publisher and delete the unassigned directory numbers (DNs). Perform these steps:

1. Go to Cisco Unified CM Administration Page > Call Routing > Route Plan Report.

   

2. Click Find and you will find a report similar to this one:

   

3. Check for any unassigned DN. If there are any, delete those extensions or else the assigned range will be exhausted and the phones will fail to register.

89xx/99xx phones fail to get an IP address via DHCP

Certain DHCP servers do not like the large packet size of the 9900 DHCP request packet and are rejecting it. The same DHCP servers have no issues offering leases to 7900 series phones.

Solution

Perform either of these steps in order to resolve the issue:

• Use a static IP address.

• Check the DHCP server settings in order to override the length and accept the packet.

Note: This is documented in Cisco bug ID CSCth40710 (registered customers only) .

Related Information

• IP Phone Error Message - Registration Rejected: Error DBConfig
• Voice Technology Support
• Voice and Unified Communications Product Support
• Troubleshooting Cisco IP Telephony
• Technical Support & Documentation - Cisco Systems