Help & troubleshooting for channels on your Roku device, including adding/removing channels, logging in to, authenticating, or activating a channel, channel-specific playback issues, assistance contacting channel publishers to report issues, and adjusting channel-specific settings.
Yes, most channels are only available in specific geographic regions. The Roku Channel is US only. I can't speak to the others, but it's almost certainly that the channel provider doesn't offer it in your location. You would have to contact Hulu and Amazon to ask if they would support your location, but it's completely up to them.
For the Roku Channel, I'm pretty sure the contracts they have to stream content limits them to the US, and perhaps Canada. Nothing outside North America.
Dan Roku Stick (3600), Ultra (4640), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Nvidia Shield, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.