If you're having trouble with the sound after locking your screen when using TikTok, you can try the following methods to turn it off:
Quit the TikTok app
Before locking the screen, make sure to quit the TikTok app completely. On iOS devices, you can close the app by double-tapping the Home button or by swiping up on the bottom edge (for devices with facial recognition) and then swiping up on the TikTok app preview.
Turn off background app refresh
In "Settings", find the "General" or "Apps" setting, then find "Background App Refresh" to turn off background refresh for TikTok.
Check your system settings
Check your voice and settings in Settings to make sure there are no settings that allow apps to apply sounds in the background.
Update apps and operating systems
Make sure your TikTok app and mobile operating system are up to date. Sometimes, older versions of apps or systems can have these issues.
Restart your phone
If none of the above works, try restarting your phone, which can sometimes fix unexpected software issues.
Check your system's audio settings
On some phones, the system's audio settings may allow *** to continue on the lock screen. Check these settings and make adjustments.
If none of these steps work, it may be a problem with the app itself. You can try contacting Douyin customer service or checking the app store to see if other users have reported similar issues. Also, expect the next update of the app that might fix the issue.