Help & troubleshooting for channels on your Roku device, including adding/removing channels, logging in to, authenticating, or activating a channel, channel-specific playback issues, assistance contacting channel publishers to report issues, and adjusting channel-specific settings.
I'm not following your question. The only time a code appears on the TV screen is during initial setup, and you say it had already been working fine. Can you be a bit more descriptive on what the device is doing, and what you are doing with the device? Did you do a hard reset and are setting the player back up? When you say screen, is it the TV screen or your computer? Is the player not connected to the network, or is it something with your user account?
Dan Roku Stick (3600), Ultra (4640), Ultra (4670), Ultra (4800), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Nvidia Shield, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.