Windows defender

1. Press Windows Key + R, type gpedit.msc and press Enter.
Navigate to Computer Configuration > Administrative Templates > Windows Components > Windows Defender Antivirus.
Make sure the setting is not disabled.
20 Open “Settings” and select “Update and Security”.
Click on “Windows Security Center” and check the status of Windows Defender Antivirus here.
If it is disabled, try to re-enable it. 2.
2 Enable antivirus from the Control Panel:
Open “Control Panel” and select “Programs” > “Programs and Features”.
Click “Turn Windows features on or off”, expand the relevant options, make sure Windows Defender antivirus is checked, and then restart your computer.

You can reset the Windows Security app to see if it resolves the issue:
1.Go to Settings > Apps > Apps & features.
2.Scroll down and find Windows Security.
3.Click it and select Advanced Options.
4.Scroll down and find the Repair and Reset options. Start with Repair and see if that fixes it. If not, try Reset.