How do I get this message off my screen?

This may be obvious but did you power down and reboot the computer?

I love my Roku but I’ve never tried to cast to it, so I don’t know IF this will work…Turn off your TV & then unplug it for 30 seconds or so…then plug back in & turn TV back on. This reboots both your TV & the included Roku device.

You could also try updating the Roku device. With any problem that I have with Roku, one of these 2 suggestions has cleared up my problem.

Doesn’t Roku have a user forum on their website? I bet somebody else has had this problem & can tell you exactly what to do.

Ok, maybe I should have added (without rebooting my computer).

I have had message popups that would not go away. I’ve had success by opening the task manager, go to processes, and end the process behind the message. Like, if it is a message saying you need to upgrade to a higher antivirus product, end your antivirus process. Then restart the computer. I’m not a tech person I just try things until I get the result I need. Or have a breakdown and call in help. :)