In early 2021, the Humax Freesat HDR 1100S set top box were affected by an issue, whereby the search function in the Youtube application did not work.
For some reason, when you selected search, the “keypad” appears for a second, then disappeared. This meant that you could no longer use the keypad to search for Youtube videos.
It took a while for a fix to be produced. The fix was meant to be rolled out to all “internet connected” Humax Freesat HDR 1100S set top boxes, but not all have had the fix. So you may have to perform the software update manually.
A copy of the fix and instructions as to how to apply the fix can be found at : https://www.satandpcguy.com/freesat/freesat-receivers/humax-freesat-set-top-boxes/freesat-humax-hdr-1100s-set-top-box/humax-freesat-hdr-1100s-youtube-issue-fix/