I gave up using the 4k express. I still have it collecting dust. I use the basic Roku which works fine. Send it back. I tried for several weeks to get it to work. The controller will mot even pair with the box.
Thanks for the post.
We would recommend checking out the troubleshooting steps provided by our Support page here: Fix your remote
Please keep us posted what you find out and we will be able to assist you further.