Phone screen was not turning off

It sounds like your Samsung Galaxy M11 might be experiencing a screen display issue where the screen remains on even when it should turn off. To troubleshoot this, you can try a few steps:

1. Check Screen Timeout Settings: Go to your phone's settings and find the "Display" or "Screen" section. Look for "Screen timeout" or similar options and set it to a desired time interval (e.g., 1 or 2 minutes).

2. Restart your Phone: Sometimes, a simple restart can resolve minor glitches. Try restarting your phone and see if the issue persists.

3. Check for Software Updates: Ensure your phone's operating system and apps are up-to-date. Sometimes, updates include bug fixes that could address this type of issue.

4. Check for Rogue Apps: An app could be causing the screen to stay on. Restart your phone in Safe Mode to see if the issue persists. If the screen behaves normally in Safe Mode, a third-party app might be causing the problem.

5. Factory Reset (as a Last Resort): If none of the above steps work, you might consider doing a factory reset on your phone. However, make sure to back up your data before doing this, as it will erase all data on your device.

If the issue continues even after trying these steps, you may want to reach out to Samsung's customer support or visit an authorized service center for further assistance.