No. With Duo Two-Factor Authentication at U-M, you can enroll any number of devices, and use multiple methods of contact for mobile devices. Several options are available, including:
- Duo Mobile app on any iOS or Android device
- SMS text a passcode to a mobile phone
- Automated phone call to a mobile phone or landline
- Obtain a hardware token
Registering multiple devices is especially helpful as a backup, in case you may be without your smartphone when you need to log in. You can enroll as many phone numbers or devices as you want as backups, including landlines and tablets you could use as an alternative until you have your primary device.
If you only have one device enrolled in Duo and it is not available to you when attempting to log in, you can call or chat the ITS Service Center for a bypass code to let you in.