Hi and welcome to the community. 
Linking the pinned topic in this category and the Help Center article below just in case you haven’t seen them. Have you tried troubleshooting using the below as reference?
FAQ: Why am I not seeing Brave Ads?
Why don’t I see any Brave Ads after enabling them?
If after troubleshooting you still have a problem, can you please test the following to help support staff troubleshoot your problem.
- Are you using a vpn? Do you have any extensions installed?
- Create a new test profile and see if you start receiving ads in the new profile?
- Download Brave Beta and/or Nightly to see if the problem still occurs.
- Try disabling and reenabling Brave Rewards, clearing history/cache for all time, exiting the browser, and reopening.
Please provide an update. Take care.