Its technical systems were hacked , so that some participants in other countries could not fully communicate .
In June 2016 , Yang organised an event in Washington D.C. to commemorate the 27th anniversary of the Tiananmen Square crackdown in China .
China 's technical systems were hacked , so that some participants in other countries could not fully communicate .
In June 2016 , Yang organised an event in Washington D.C. to commemorate the 27th anniversary of the Tiananmen Square crackdown in China .