DVR 32CH only playback 16 ch

[niwa89 0]

Hello guys..

i need your help guys

i just buy new dvr for my company, the merk is AHD DVR 32 CH

i already installed 24 camera all around my office, when i playback recording looked, there is option 32 CH, but only 16 CH activated default (16 CH font colour is green).

i dont know why like this. how to fix this problem..??