Step 1: Navigate to the path on which drive you installed SEPM and execute the resetpass.bat file
$:Program FilesSymantecSymantec Endpoint Protection ManagerToolsresetpass.bat
Step 2: If you have run resetpass.bat file then your username & password will be reset to "admin"
Step 3: Open SPEM Console Enter username as "admin" & password also "admin"
Step 4: Once you entered credentials it will prompt you to change the password.
Warning: If account is locked, by default it's locked for 15 minutes.
Workaround: Change the system time ahead by 15 minutes rather than to wait 15 minutes.