I'm Mark joy working in yahoo support technical technical support manager to solve your Error. Easy way to logout of yahoo mail on yahoo mail keeps reloading on all devices when you are logout your yahoo account due step just one click in yahoo Support we help you. Know more about yahoo and tell us your Errors just one ping in Yahoo visiting website.  

Enabling this service means the user will no longer be required to enter the password while signing and sign-out in to the email account. Yahoo account key can be best described as the notification service for login. 

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