This may be because the user downloaded or installed some applications containing adware, or clicked on malicious emails or websites with advertising links. You can try the following solutions: 1. Delete the application that contains adware. 2. Enhance security and use a secure browser and email client. 3. Install antivirus software, scan and remove malicious software. 4. Update the mobile phone system to ensure that security patches are installed. 5. Enable AdBlock Plus on Android phones. 6. Back up mobile phone data, restore factory settings, and remove all malicious software and advertisements.