When verifying new devices, you may receive a "Device Verification Failed" error after tapping on the emailed link. Verification must happen in the same browser session on the same device you are trying to verify on. For instance, if you are in Google Chrome, and clicking on the verification link opens Safari by default, the device verification will fail. Additionally, if you attempt to login on a desktop computer, and you tap the link on your phone, it will also fail.
Check to ensure that you are not accidently opening up a separate browser tab or trying to verify on a separate device. Once your device is verified, you should not be asked to do this again.