This issue occurs when:

  • A Polycom VVX500 displays Invalid Hostname
  • The phone is registering & can make/recieve calls without issue

If the above are not true, you may be dealing with:

  • Important: If the phone Cannot make calls, you are looking at the 'Extension 999/Invalid Hostname' issue

Possible Causes

  • This issue is caused by the customer doing a soft reboot on the phone using the phone menu (Home button > Settings > Basic  > Restart Phone) key/touch sequence.
  • The phone attempts to load the idle home screen (with DID, extension, enterprise name, etc.) too quickly (before it has established network connectivity), and shows Invalid Hostname. However, by the time the phone attempts to register, the network connection has been set up, so it is able to make/recieve calls normally.


The customer can remedy this situation by swiping either left or right on the screen: This will trigger the phone to query our configuration server again, causing it to load the correct idle home screen.

Doing a 'hard' reboot (power cycle: Unplug it > Wait for ~30 seconds > Plug it back in) should force the phone to reinitialize itself and wait for until the network connection is fully ready before querying our configuration server for the idle home screen.
Dev has informed Polycom about this issue in the past and they have a plan to fix it in newer Polycom firmware.