I can’t connect to battle.net

I tried to play a game using the game platform Battle.net, but I couldn't log in. I contacted support and tried many solutions but couldn't find a solution. Finally, support told me to contact my provider, so I came here.

Additional information is provided below:

・I can log in to the Battle.net website, but I can't log in to the Battle.net app launched from my desktop.

・I can log in if I use a VPN or my smartphone data line, but as soon as I switch to my home Wi-Fi I am immediately logged out.

・I tried using my smartphone, and can log in using my smartphone data line, but not at home Wi-Fi.