Cisco IP Phone “Host Not Found” error.

Introduction

This post explains why you are getting “Host Not Found” error on your newly registered IP phone’s display and how to fix it.

Why “Host Not Found” error?

The reason you are getting this error is that when you autoregister a brand new IP phone, it attempts to take you through the self-provision wizard, but can’t reach it.

Quick Fix

To fix this problem for a particular phone, go to the Phone Configuration page and make sure the Idle and Idle timer fields are blank, like shown below:

Erasing those values will fix the problem for the current phone, but all new phones will get them populated if you do not delete those values from the auto registration template.

Permanent Fix

All auto registered IP phones take their settings from the auto registration template, which is configured on Cisco Unified CM Configuration Page:

To edit that Auto-registration Template, go to
User Management -> User/Phone Add -> Universal Device Template.

Select Auto-registration Template. Scroll down to Service Configuration Settings and make sure that Idle and Idle Timer (seconds) are blank:

From now on newly registered IP phones won’t attempt to access the Self-Provision Service.

Conclusion

Now you know how to fix “Host Not Found” error on the Cisco IP Phones.