Sorry that you are seeing this issue.
Can you please let us know which file type you are trying to debug? Also share the .log file located at workspace dir/.metadata/.log (rename the extension to .txt and attach the file here)
Unfortunately, it looks like CodeMix is broken in newer Eclipse versions which is why the Extensions are not being loaded.
The dev team is currently looking into it. If you can downgrade Eclipse version, then please install CodeMix to Eclipse 2020-09 and apply the patch as suggested in my previous response.