Dzzy-
I just tried out Pluto on both a Streaming Stick 3800 and a Streaming Stick 4K+ 3821. No problems with either one with viewing programs from the live channel guide, or from on demand.
After removing the channel, but BEFORE reinstalling it, be sure RESTART** your Roku to clear its memory cache. Without the restart you may not get a clean reinstall. This is not a cure-all but at least it will assure you of having an uncorrupted copy of the current version of the channel app.
Depending on your Roku model number you'll find the "System restart" option under either "Settings > System > Power" or under "Settings > System". If you don't have sufficient control to use the menus, or if it is just more convenient, you can also restart by pulling the power plug for a short while, then plugging it back in.
** For Roku TV owners who might read this: On a Roku TV with "Fast TV Start" enabled, turning the TV off/on only puts you in/out of a low power standby state, it does NOT give you a complete restart. Use the methods above.
