Teamview12 super lag and resolution drop down

Hello , I'm always using the teamviewer to use computer A (win XP or iphone) control the computer B(win 10), and there are no problem.

But start from few days ago, when i teamviewer the computer B after around 15mins, the computer B suddenly become slow, and not easy to control and then i remote to restart it, the resolution from 1920*1080 drop to 1024* 768, and the software viewport will be blanked (white), all control is work but still lag.

If i using the teamviewer function to restart it, the resolution still keep in 1024*768.

But i go back home and normal use the computer B without teamviewer, everything is fine.
I have reinstalled the teamviewer once time, and still have this problem.

Do you know what problem is going on? It the problem about the network or others? thanks so much.