What does Authentication failed mean?

[AC Question]

I am getting this mssg from my gmaiI on my Android.
When I open the mssg, it says Gmail requires authentication. This happens all day long, eventhough I am not using my phone for anything. The mssg also says account could be locked due to frequent login attempts, when I have not attempted to lognin for any reason.
Does anyone know how I can get rid of this annoying mssg?

 

[B. Diddy]

Welcome to Android Central! Which phone? Are you using the stock Email app, or the Gmail app?

If you're using the stock Email app, go to its Settings, select the Gmail account and remove it, then add it back again.

If you're using the Gmail app, go to Settings>Accounts-Google​, remove your Google account, then add it back again.