Open QQ and enter the message setting page.
On the Information Settings page, find the "More Features" option.
In the "More Features" option, find the notification interface of the small world.
Enter the notification interface of small world, find the window below, and click the "switch" on the right.
After the prompt box pops up, confirm the open status again, and then click to successfully enable the notification.
If you want to turn off the advertisement completely, you can try to download the client file again and reinstall it to solve the problem.
The above methods are for reference only. If the problem cannot be solved, please consult Tencent Customer Service for more accurate information.