First, please check that your YouTube channel is fully confirmed on YouTube and make sure your privacy settings allow the channel to be open for search. You need to have at least one video uploaded to your channel for it to be recognized.
Next, visit Manage my Channels and enter the full URL for your YouTube channel. It will look something like this: https://www.youtube.com/c/channelname
If the tips above do not work and you continue to have an issue linking your YouTube channel to your account, please contact us for further assistance. Be sure to include the name of your YouTube Channel in the message.