Thank you @EA_Aljo. This does not help unfortunately. I tried it and tried port forwarding. The problem seems more complicated. We tried another game (i.e. PES20) and we have the same outcome with the error code (NP-40837-2). But everything turns normal when I use another internet network ! My internet provider told me since everything seems normal in their system (ports are open, no packet loss) and the internet works with other devices, it is not their issue. I am so frustrated right now. I will try another modem. But if you still have tips left, please share them with me.