Can you post a picture? "No signal" usually comes from the TV, but you're seeing the Roku Home Screen. "No connection" means it's not connected to your Wi-Fi. The remote should still work, so try new batteries. Have you tried disconnecting the stick from the TV and the USB power cable and then reconnecting?
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.