xperia device is locked and the screen says “Protected.” How do I unlock it ?

• The Protected screen is displayed when your device is in
•  Lockdown mode.
• Currently
  • Xperia M4 Aqua
  • Xperia C4
  • Xperia Z4 Table
•  Lockdown mode is a feature of Protection by my Xperia and is
•  triggered when
•  unusual activities are detected or performed on your device. 
• Such activities can include a factory data reset, a software repair
•  or the erasure of user data.
• In order to recover your device from Lockdown mode, 
• you need to have
•  the Google™ account credentials you used to set up the Protection 
• by my Xperia service You also need access to a Wi-Fi® network
• If you have forgotten the username or password for 
• the Google™ account 
• that you used to set up the Protection by my Xperia service, 
• you can recover
•  your username or password by using the 
• Google™ Account Recovery page
• . If your Xperia™ device is locked and displaying the Protected screen, 
• you can access the Internet and recover your 
• Google™ account password or username using a different device.
• If you have several Google™ accounts and don’t know
•  which one is linked to 
• the Protection by my Xperia service, you can check it on the
•  myxperia.sonymobile.com 
• website. If your Xperia™ device is locked and displaying the
•  Protected screen,
•  you can access the Internet and check your 
• Google™ account using a different device.
• To prevent Lockdown mode from recurring, 
• you can deactivate Protection by my Xperia on your device.
•  Note that if you disable this feature, you will no longer
•  benefit from the additional security  layer that the my Xperia 
• service provides.
• original link
•  https://support.sonymobile.com/global-en/xperiac4/faq/Lockdown-mode-and-protected-screen/