Hi Bina!
Are you having an issue getting translations to show or are you just trying to resolve the 404 error you are seeing? You could be running into a known issue laid out in the FAQ linked below. This should be resolved for less noise in the browser console in more recent versions of the UUX platform (4.6.1.11+).
Why am I seeing 404 errors in the developer console from q2-tecton-sdk?
If you are having trouble getting translations deployed with your extension working correctly, please open a ticket in the developer portal and we can take a look at your extension in detail. Thanks!