You can use Cisco Webex to check whether your ATA is online or offline. You may want to do so if your analog phone is not working as expected.
If your phone is not functioning then your ATA may be offline.
Sign in to Cisco Webex Settings .
Click Personalize Settings.
Click Call Settings.
Find your ATA device in the list of your devices.
View your ATA status, which is either Online or Offline.