While there are several ways to help troubleshoot and ameliorate the problem, there’s unfortunately no “one size fits all” silver bullet fix that will remedy it for everyone.

Clear your DNS cache, which should fix the 400 Bad Request error if it's being caused by outdated DNS records that your computer is storing.

How do I fix error 400 on my smart TV? If you see error 400 while watching online videos on your smart TV, first try reloading the video, then clear the app cache in your TV's settings.

Fix 400, That’s an error, Your client has issued a malformed or illegal request on Chrome which is encountered while watching YouTube videos.