I've been posting comments on Youtube without problems for years. Today however something's changed. I signed in as normal and attempted to post a comment about a video, using the "Share your thoughts" comment box. "Public" and "Post" were beneath the box. I typed in the message but "Post" was greyed out and wouldn't respond. I discovered however that if I click on "Reply" beneath the posts, it works and my reply appears. Simply put,I can reply but not post. Can anyone advise please?