Thanks for reporting this issue here in the Roku Community, @Yuriy!
We understand that you're experiencing trouble streaming with these apps and we'd like to help you get back on streaming.
Have you tried rebooting your router? If not, try unplugging it from the power outlet and see if the buffering issues disappear.
Please let us know how it goes.
All the best,
Emman
Emmanuel-D.
Roku Community Moderator