The first thing you should do is update youtube-dl. YouTube Word Finder uses youtube-dl under the hood, and so any weird issues shown in the console probably stem from issues with youtube-dl. Press the 'Update youtube-dl' button in the bottom left corner of the app to update it.
If this doesn't work, there may be an issue with the current latest release of youtube-dl. However, you may find other forks with fixes patched in on GitHub or anywhere else. If you want to try a working unofficial version of youtube-dl, you can provide the path to the custom binary executable from the app.
If that didn't work, you may need to provide a cookies text file, for which there is a text input in the app. More instructions can be found here: https://github.com/ytdl-org/youtube-dl/blob/master/README.md#how-do-i-pass-cookies-to-youtube-dl or here: https://github.com/l1ving/youtube-dl#how-do-i-pass-cookies-to-youtube-dl
