Hi Sujith M2,
Thank you for posting in the Microsoft Community Forums.
Ensure that the account lockout policy has been properly configured in the appropriate Group Policy Object (GPO):
Account Lockout Threshold: Set to a reasonable value, such as 5 invalid login attempts.
Account Lockout Duration: Set how long an account will be automatically unlocked after it has been locked, usually 30 minutes.
After Reset Account Lockout Counter: Set how long after which the Invalid Login Attempts counter is reset, usually also 30 minutes.
Link GPO to correct OU:
Make sure you link the GPO to the correct organizational unit (OU) containing the users or computers to which you wish to apply these policies.
Right-click on the GPO, select “Link Existing GPO”, and then select the GPO you created or edited previously.
Run the following command on the client computer to force an update to the group policy:
gpupdate /force
Check if the result of the Group Policy update was successful.
Then view the events related to the Group Policy in the Event Viewer, especially the error or warning messages.
Best regards
Neuvi Jiang