Non- techie query - YouTube - Restricted mode - Can't turn off

By way of explanation - I have been unable to view YouTube videos for some weeks now & one of very few ‘help’ responses I found online suggested that the issue was likely due to something in my Antivirus so here I am desperately hoping the answer might be here at Avast (the only AV I am using. I am Running Windows 10 with Defender turned off)
Message: Video unavailable. This video is restricted. Try signing in with a Google Apps account.

  1. I am signed in with a Gmail account on a private PC (laptop) so there shouldn’t be a Network Admin.
  2. I am unable to change the Restricted Setting - It is set to ‘On’
  3. When I try change On to Off I see:
    Restricted Mode
    Restricted Mode hides videos that may contain inappropriate content flagged by users and other signals. No filter is 100% accurate, but it should help you avoid most inappropriate content.
    Restricted Mode is enabled by your network administrator.
  4. Changing browser makes no difference, nor does cold booting the router and laptop (tried many times)

Sounds like an age restriction, could you provide an example…!?