You provided little useful information. The most reliable way to upload a file to YouTube or Vimeo is to create a high quality video with the AVCHD choices under Publish and Share and then use the YouTube or Vimeo uploader.
What version of Premiere Elements and on what computer operating system is it running?
What is the duration of the Timeline that you are trying to upload to YouTube using a Premiere Elements built in feature?
When you try to upload to YouTube, at what phase of the process are you stopped and what error messages, if any, are associated with the failed process?
Have you tried the export of your Timeline to a file saved to the computer hard drive from where you upload that file to YouTube at the YouTube web site? If so, does that work. That type of information would help to rule out YouTube account issue among other things. Have you checked your Internet connection and looked at using a different default browser?
The answers will be in the details. So, please review and consider, and give details necessary for us to help you.
Any questions or need clarification, please do not hesitate to ask.