Unable to Register a Webex Room Device or Webex Call IP Phone to Webex

If a customer is unable to register their Webex endpoint or phone to Webex, it is most often due to a network issue. A common cause of this is the use of a Meraki router or security appliance on default settings.

Unable to register a Webex Room Device or Webex Call IP Phone to Cisco.

I can't register my phone with Webex Call.

I can't register a Webex Room Device.


When attempting to register a phone, TelePresence device, or Cisco Webex ATA devices to Webex, a customer may receive errors such as the following:

  • 'Not able to connect to Webex service'
  • Warnings that an NTP (Network Time Protocol) server is unreachable
  • their time may be set to a day from November 2015
  • a certificate error
  • security error
  • device may be stuck at 'Registering'
Possible Causes:
  • The customer is using a Meraki security device or router on their network.
    • This is commonly caused by Meraki routers or security appliance devices, which when functioning as a DHCP server, will advertise their own IP address as the network's NTP server in DHCP option 42. Unfortunately, these devices do not actually host a network-reachable NTP server, so devices such as Cisco 7800 and 8800 series phones will attempt to connect to the Meraki device to update their time, but the connection will fail since no NTP server is accessible.
  • The device is unable to reach an NTP server and set its time to the correct time and date.
    • This is typically due to one of two reasons:
      • NTP (UDP port 123 from the device to the Internet) is being blocked by the network, firewall or router.
      • The network's DHCP server is broadcasting an unusable NTP server on option 42.

If the customer has Meraki security on their network:

One workaround is to reconfigure the Meraki device to advertise a valid NTP server IP address. We recommend that a customer first run the command nslookup 0.tandberg.pool.ntp.org and copy the first IP address which is returned by their DNS server. Afterwards, they can follow Meraki's documented instructions to set a custom DHCP option value for option 42, and then reboot the phone or endpoint. Once the device boots back up, it should query the DHCP server for an IP address, receive the new NTP server IP address and connect to it, update its time, and then one should be able to continue the regular activation sequence.

If NTP (UDP port 123) is blocked

This will need to be resolved by the customer's network, firewall, or security and administration teams.

A workaround for this is to manually update the device's firmware to the newest Webex compatible version. This can be done by following the instructions on upgrade.cisco.com. Please note that as of 15 October 2016, upgrade.cisco.com is only compatible with 7800 series, 8800 series, and DX series devices.

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