Your profile doesn't list a location, although your username indicates it might be Japan.
Not all Roku features are available in all area. I believe Roku is only supported in United States, Canada, France, United Kingdom, Argentina, Chile, Colombia, Costa Rica, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama, & Peru.
Some features might not even be available in certain of those locations. Outside those locations, there is a greater chance that functionality isn't available.
Basil
https://www.basilsblog.com/
Roku Ultra (4660)
Apple TV (5th gen), TiVo
Previous:
Roku boxes from every generation.
Apple TV (2nd, 3rd, 4th gen)