Hi @ChristineB, I’d guess the culprit would be some kind of network error since the app doesn’t require much storage and shouldn’t use much RAM. But it does require a network connection for most functionality (particularly on the first run), so you might ask if he was on wifi or cellular and see if the problem is fixed by refreshing (pull down from the top of the screen) or by force-quitting and restarting the app.
In any case, feel free to contact me directly for app support. I think you have my info, but I’ll drop you a line about this shortly.