Just making sure you have done the following:
Unlock your Windows 10 phone remotely
- Try unlocking your Windows 10 device remotely if you get this message: "This device has been locked for security reasons. Connect your device to a power source for at least two hours and then try again." The key is to reset your PIN through
account.microsoft.com. If you use remote unlock, your logon PIN will be protected by Windows instead of your device's security system.
- Go to account.microsoft.com.
- Sign in with the same Microsoft account you use on the phone.
- Click the Find my phone link.
- Press Lock.
- Enter a new PIN. Now you'll be able to unlock your phone with your new PIN.
- To go back to having your logon PIN protected by your device’s security system, make sure the device has been on for at least 2 hours. Go to Settings Gear-shaped Settings icon > Accounts > Sign-in options page and select "I forgot my PIN". Enter your Microsoft account info, verify your identity, and set the PIN for the device.