To confirm the ownership of your YouTube account, navigate to the settings , then the ‘Channel’ subsection and select the link ‘Feature eligibility’. To confirm the ownership of the channel, it is necessary to provide a phone number verification. Make sure that you have verified your channel because it allows you to perform important actions such as uploading videos which are longer than 15 minutes, adding custom thumbnails and it is the first step to unlocking additional features to upload more content and monetize in the future.