When you make a transaction or withdrawal on XS2, you need an XSKey. The first time you do this, it will be generated and tied to the device and browser (or XS2 app) combination you are using. You can view your devices and XSKeys here: https://xs2.exchange/account/summary
You can always sign in with additional devices and browsers but you will need to authorize them from a device/browser combination that already has an XSKey. Until then, you will not be able to trade or withdraw from your additional device. Managing your XSkeys can be done via the Account link. Here you can verify devices by clicking "Add XSKey" under the unverified device. You can also rename devices here for easy reference.
1 From the device that has an XSKey, find the device/browser combination that does not have an XSKey. Make sure you logged in from the device that you want to add first!
2 Click Add XSKey
WARNING: your XSKey is kept in your mobile app's data or browser's site-data, so clearing app-data or browser-history that includes the site-data option will make you lose your XSKey on that device.
Our tip is to keep your XSKey on 2 devices (your phone plus your laptop for example), so if you ever lose it from one of them you can add it again from the other device (a simple click from the account-page).