@CaroleC Try to answer all questions given in the template to clarify your issue like which OS or whether using VPN etc.
Do you mean you can’t toggle on Ads on brave://rewards or that you are not receiving ads?
There is a minimum threshold to verify you wallet which you should see on brave://rewards. If you don’t see any minimum threshold then you can go ahead and verify your wallet. You can only withdraw your BATs from a verified wallet otherwise it will keep accumulating in your browser wallet