This very general question/problem. Some background info may help like what application is running, can browse while Tuotu off or not etc. Here some possible answer...

Maybe you set open to many MAX 1/2 TCP connection in Tuotu general setting. Please set limit to "8". From my experience using those P2P clients, it really doesn't matter much and 8 is a good figure for about 10 task running in Tuotu. Too much, you saturate and kill eg. "cannot surf internet when running situation".

Too many task, upload given, connections by P2P at once also can cause this.

Please have try the software "cfospeed", maybe can help. It help shape, queue your http packets priority and maybe can browse better.