Why can't I log in to my Google Account in Fully Kiosk Browser?

Some users report an issue (“Couldn’t sign you in. This browser or app may not be secure”) when trying to log in to a Google Account in Fully Kiosk Browser.

For security reasons, Google apparently decided to disallow using a Google Account in Android Webview (which is used by Fully Kiosk and many other apps). For now, Android Webview doesn’t seem to be blocked completely. Depending on unknown factors (possibly the OS version, network, or location), some users can still sign in to a Google Account, while others experience this issue.

The official solution should allow less secure apps to sign in, as described here. However, users have reported that it doesn’t have any effect for Android Webview.

The current workaround is to select Edge as Fake User Agent in Fully Kiosk Advanced Web Settings. However, it’s unclear how long this will work. If Google decides to block all logins in Android Webview, there will be no workaround. Unfortunately, this is outside our control.