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 verification will fail.
Check to ensure that you are not accidently opening 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.