How to get out of login loop

I have just bought an Acer Iconia One 8 for a gift. I charged it overnight and it booted, I was asked for a Google account, gave it the username and password, I received Google's challenge and confirmed that it was my account (shared with my husband, for whom the gift is intended). However, I then got the message

"This device was reset. To continue, sign in with a Google Account that was previously synced on this device

Enter your email"

This is a brand new device - the security tag on the box was unbroken. Google alerts tell me that there has been a successful login each time I tried it. I can't see how to get out of this?