Here is the way to turn it off Reactivation Lock from Google’s website.
Log into https://myaccount.google.com with your Google email address and password.
“Under Sign In & Security >” On left of screen - click on “Device Activity And Notifications”.
On the right of the screen click “Recent security events” and click on “REVIEW DEVICES”
You will now see all devices linked to your Google account.
Click on every single device which you want to remove (inc. the one mentioned above) and select REMOVE under account access.