Roku Streaming Stick 3810RW ver 9.1.0 build 4111-50 Screen Saver Mode non-responsive when turning TV back on. TV volume responds to Roku remote but Roku does not respond and is stuck in screen saver mode (Subaru scrnsvr) until I jiggle it in the port or unplug/plugin from the port or unplug/plugin the Roku power cord. Happens every-time the TV is turned off and back on. It used to work fine for months but just started this "stuck in screensaver mode" recently. My other two Roku devices work fine. This only happens when the TV is turned off for a while (hours or overnight) then turned back on.
This may relate to a communication issue with your remote control. Try downloading the free Roku Mobile app, and use the built-in remote control functionality to press any button. The player should respond to this input, and wake out of screensaver mode.
You might also double check that your wireless router is broadcasting a 5GHz Wi-Fi network and ensure your Streaming Stick+ is connected to that network SSID, and/or try changing the wireless broadcast channel on your router to see if this helps. Your ISP or wireless router manufacturer can assist you with both of those items.