I cant Update Google play services as it says "Authentication is required. You need to sign into your google account"

I keep getting nonification updates the I need to Update Google Play services and that Google Play services wont run unless updated, wh I click on the nonification. It bring me to Googl
play services but it says “Authentication is required. You need to sign into your google account which I checked in Accounts, I was signed in. I need to get the Play services to work as most of my apps like Snapchat rely on it.