Hi @grysik,
A warm welcome here in the Roku Community!
We will be delighted to assist you with your issue on your Roku Express. Please make sure that all the cables are plugged in firmly and properly.
If the problem still persists, you can factory reset the Roku Express by locating the reset button and pressing/holding the button for 10 seconds.
If the problem still persists, please keep us posted.
Best regards,
John
John
Roku Community Moderator