Streambars don't turn off. That power button on the remote only affects the TV. If the light on the Streambar doesn't come on and/or you don't get the startup animation on your TV screen when you disconnect and reconnect the power it's probably time to start investigating a warranty return:
Step-by-step instructions for returns and warranty replacements | Official Roku Support
Roku Community Streaming Expert
Help others find this answer and click "Accept as Solution."
If you appreciate my answer, maybe give me a Kudo.
I am not a Roku employee.
