Network problems. On the one hand is the student's network on the other hand is the teacher's network leads to live lecture lagging, if the APP lagging, is the APP server in the upgrade will appear lagging, you can turn off the restart. China Agricultural University, referred to as "China Agricultural University", is located in Beijing, is the People's Republic of China *** and the Ministry of Education directly under the People's Republic of China, the People's Republic of China *** and the State Ministry of Water Resources, the People's Republic of China *** and the State Ministry of Agriculture and Rural Affairs of the People's Republic of China and the Beijing Municipal Government **** build a national key universities, ranked "double first-class "Construction of colleges and universities," "985 project", "211 project", selected "basic disciplines enrollment reform pilot", 2011 Program", "111 Program", "Excellence in Engineer Education and Training Program", "Excellence in Agricultural and Forestry Talent Education and Training Program", "National High-Level University Postgraduate Program", "Chinese Government Scholarship Program", "National University Students Cultural Quality Education Base", and "China - China International Student Scholarship Program". It is also a member of the "10+10" cooperative research alliance between China and the University of California system.