Hardware capacity
My system alerts that I have no hardware capacity when I try to monitor a channel.
Please check your system Hardware capacity graph and ensure that you have enough unused points to monitor the channel.
Note, that channel monitoring may require a different number of points, depending on the codec, resolution, bitrate, framerate.
For example, the SD HEVC channel will take 2 points, H264 more than 20Mb bitrate - 10 points, etc.