These instructions only work if you have access to your enrolled device(s). If you do not have access, please refer to the article: Adding a new device to Duo and I don't have access to the old device or phone number
3. If Duo Mobile authentication method is selected for the newly added device, the following prompt will appear on the Duo self-service portal:
Choose a method to confirm ownership and the owner of the newly added device will receive a passcode on their mobile device. Get this passcode number from them and enter it into the next screen and click Verify to add the device:
Users will receive an email notification with the subject line “Device, [device name] Added” or “Device, [device name] Removed” or a Duo Mobile app notification when an authentication device is added or removed from their Duo account.
What do I do next?
For personal netID accounts, select Yes, this was me if you recently added or removed a device.
If you did not add or remove a device, select the No, this wasn't me option.
Shared Service Account Notifications
To avoid confusion for a shared service account, before adding or removing devices for the Duo account, notify any other Duo enrolled users that when they receive such a prompt they will need to select Yes, this was me.
Selecting No, this wasn't me will create a ticket for the Service Desk to investigate further.
Example of Duo Mobile notification:
Example of Email notification: