denial of entry visa with no reason given.

Am joseph dyabe,from kampala uganda.
I am a business man importing goods from chinese cities. i have been travelling to PRC for business for the last 3 years(2011-2013). in 2014 january i applied as usual and i was denied one without reason why and told to apply again after one year (2015 january). after one year i applied again and have been denied with no explanation why.told again to come again after one year(2016). my question is why am i being denied without letting me know why?