This is the first step of any Genius POS install. Until the location is added to the Mobile/NextGen group, the devices have nothing to sign in to.

Steps

1. Log in to the Admin Console and open the correct account and location.
2. In the Main Menu, click Location Setup.
3. On the Location Settings screen, click the Mobile/NextGen Settings tab.
4. Click Add Location to Mobile/NextGen Group.

Then do this, or the site will call you

Force close and restart the Pay App on every non NextGen device on the network, including iPads and kiosks. This resets their socket connections. Skipping it leaves the site with intermittent sync and performance problems that look like a network fault.

Verify

Open the Genius app on a NextGen device. It should now accept a Device Login Code. See Log in to the Genius POS.

Source: Global Payments Genius POS Setup Guide. Newly built article, pending review.