Today I tried my first upload to YouTube via Premiere Elements. But despite putting in my correct user-name & password it would not recognise them. I later on got an e-mail from Google about a Suspicious sign in prevented! I eventually uploaded through YouTube direct. But how can I get YouTube to accept an upload via Elements?
About the time that YouTube went Google (with Google sign-ins), a lot of people began having the same problem. In most cases, just completely rewriting the info in PrE helped, but when it did not, then doing the Share, and Upload method (that worked for you), did.
Note: one other issue with YouTube, and extended accounts, is that PrE 10 still had the older 10 min. Duration limit, so Share and Upload was the only way around that. In your case, however, that does not seem to be the issue, as you are not even able to get to the point of Uploading, and it is at the initial sign-in level, that you are experiencing problems.
When I logged onto my YouTube account today there was an additional message about suspicious activity. It had a button where you could confirm it was you. You them had to use that login software ie Pre 10 within 10 minutes. And it allowed me through! Thanks everyone.