Clearing the cache is often all that you need to do to fix the problem:
https://support.google.com/accounts/answer/32050?vid=0-147414495135-1483031507151
If that doesn't help it might be that you're using an extension (such as an ad-blocker or Youtube downloader) which is causing the problem. Try browsing in incognito mode. (
https://support.google.com/chrome/answer/95464?hl=en ). If the problem disappears you'll know that you'll need to get rid of a dodgy extension (which requires a bit of trial and error to find the appropriate one).