QQ shows unread messages, but it can't be found. What is the reason?

There may be a message informing the digital card, so the unread message cannot be found. You can clear the number in the message interface by dragging the notification number. After opening QQ, click "Message" in the lower left corner to enter the message interface. At this point, press and hold the "notification number" on the message with your finger. Hold down the number and drag it to the upper right corner, as shown below. At first, the number is still connected with the message, and then it will become a red circle number when you drag it out. At this point, you can clear the number on the message by releasing the dragged finger.

QQ:

QQ, short for Tencent QQ, is an instant messaging software based on the Internet. QQ has covered many mainstream platforms such as Windows, macOS, iPadOS, Android, iOS, Windows Phone and Linux. Its symbol is a little penguin wearing a red scarf. Tencent QQ supports online chat, video call, point-to-point breakpoint file transfer, file sharing, network hard disk, custom panel, QQ mailbox and other functions, and can connect various communication terminals.