Here’s what we suggest:
Delete the app and then reinstall it (Sometimes an app can have corrupt data that a fresh install usually fixes).
Turn off your device for a few minutes, then back on.
Upgrade your browser to the newest one available. Here's another link to help with that: Browser Upgrade.
Clear your cache- ChessKid Article - Cache Cleanup. (Too many temporary internet files on your device can cause it to lag.)
Update your device's Operating System - Update Apple/iOS device. Update your Android device.
If you need further assistance, please EMAIL US.