I can't seem to post a video to you tube. In movie maker, the box on the top right says I a signed in (although it doesn't show my profile picture) and I can click on the links to go to 'view my profile' and 'view account info' but when I click to post to YouTube it tells me 'the video wasn't published correctly, please sign in with your e-mail and password'. It then signs me out according to the box on the top right. I managed to publish a different video yesterday with no issues and nothing (e-mail / password) has changed since then.

Any ideas?