If you are trying to view a video and instead you are getting the error "This video is restricted. It must be approved for you to view it", you will need to disable "Restricted Mode" on YouTube.
To disable the setting, log into YouTube using your Google account. Scroll down to the bottom of any YouTube page and click on the Restricted Mode button. Select the "Off" option to disable restricted mode on your browser and click on the "Save" button.
You can find more information about Restricted Mode on Google's support website: