You can't access YouTube for Mobile Web with your account

My daughter is getting this message every time she tries to access YouTube on Safari, “Sorry, you can't access YouTube for Mobile Web with your account”. I currently manage her account under our "family" and I gave her access to use YouTube however she still can't do it. I have tried different recommendations we found online but it does not work. I will appreciate if you can help me find out how can I help her gain access again to YouTube on Safari.

Thank you,

[Re-Titled by Moderator]