I acknowledged this problem comes from my connection.

This WPA2-Enterprise WiFi I'm using won't let me log in to the game,
let me see some names on start screen for split-seconds when connected,
and shuts itself down, for years

I have tried using different WiFi connection(WPA2-Personal) and it works,
yet that isn't what can I afford to use everyday.

I tried turning off my Firewall and it worked for a single night.
(EDIT : I also do not have antivirus program installed.)
And I'm here.

Can anyone tell me better solution than finding a new WiFi connection?