“You have lost your online connection. Check your home network.” - HELP PLEASE

I'm having trouble: You lost your connection to your opponent. We'll check the match report to see who won and who lost. Everyone who plays online, what is it? I've been playing every year and I've never encountered this problem. After playing for 30 seconds, it disconnects and says: You lost your connection to your opponent. We'll check the match report to see who won and who lost.