Hi Jo,
As John suggests, you should try to run the 'Web Upgrade' again as soon as you can. The aim is to see 'BB1 Mar 09 2020' in the Stats screen. This is the latest current software version which contains a number of fixes for YouTube downloading problems.
If the Web Upgrade fails, try rebooting your router at some convenient time and re-run the Web Upgrade again.
If the Web Upgrade keeps failing, let us know here and we'll try and help you to progress.
Regards,
Peter.