FortiClient SSL VPN Client Connection Error (Android)

FortiClient version (7.4.2.0179) which was installed on android version14 that was not successfully connected. It still shows connecting problem to SSL VPN. That problem occurred in all android devices in my organization which was using mobile internet SIM-network. All android apk are updated in google play store.

But FortiClient version (7.4.0.1658) which was installed on window 10 tablet with the same mobile operation SIM-network, that was successfully connected SSL VPN client.

What is the problem? 

Best Regards,

Johnie Zaw