Why am I getting error message 'App Check Failed' when trying to log into the One4all App on my Android device?

App check is a security feature which your phone must pass to enable use of the One4all App. There can be multiple scenarios where app check might fail:

-Poor network connection

-Outdated Google Play Store app in the device

-Outdated Google Play Services in the device

-Device rooted or compromised

-One4All not installed from play store

-Device Date/Time not set correctly

Note this is not an exhaustive list of scenarios, but they are the most common ones.

These scenarios can be troubleshooted and resolved by following below steps:

-Ensure the device has a proper network connection, turn off internet connection and turn back on

-Update the Google Play Store app following the steps listed here in the official site

-Update the Google Play Services following the steps listed here in the official site

-Clear cache and data from Google play store and Google play services following the steps listed here in the official site

-Restart the device

-Uninstall and reinstall One4All app from the Google Play store and try fresh login

-Ensure Date/Time is correctly set in the device following the steps listed here in the official site