I have Roku 4230x
Serial: 4E653T056939
Software version 12.0.0. build 4184-04
I have loaded the Roku Channel but none of the content when play is selected actually plays. Nothing happens.
I have removed and replaced added channel, reset router but no difference.
What you're trying to do isn't supported and discussion isn't permitted here.
Roku Community Guidelines - Roku Community
Better?
Not really. The answer is that The Roku Channel is only supported in certain regions, none of which are in Africa.