The error message "Connection Error! Failed to Connect!. Please check your internet connection and try again" could be due to 2 things
The mobile device do not have internet access
Security token expiry
Luckily it's very easy to solve the problem. All you need to do is turn on internet. Uninstall and reinstall the app.
iOS App Store -> https://uk297.app.goo.gl/betterhr
Android Play Store -> https://uk297.app.goo.gl/betterhr