With CONXTD on iOS, you are required to login the first time you install the app on your device. Once you do this, as default, your password will be stored in iOS. Each time you open CONXTD and it goes to the loading screen it is checking the password saved within iOS. If you change the password from another device or on desktop, the app will go back to the start up screen and the new password will be required to gain access.
There are further security options in the settings of the app within iOS: Settings, scroll down to CONXTD in the list of apps.
To stay logged into CONXTD ensure 'Stay Logged In' is enabled
If you would like the added security of requiring Touch ID authentication when opening the app (after 30mins of inactivity), disable 'Stay Logged In' and keep 'Use Touch ID When Available' Enabled
If both Touch ID and Stay Logged In are disabled then you will be asked for your password each time you open the app after 30mins of inactivity.