Registration Error, second user app

[Carl4]

Installed UL3 2nd Gen and setup app in my Samsung - works fine. Setup wife as user and send email invite, she loads app, goes to device list and it scans and finds the UL3, touch it and immediately get Registration Error. Have logged out and back in, deleted app and reinstalled, reset device, deleted device and started over - always get Registration Error on her Apple phone app.